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      Abbreviated rules   07/28/2017

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Probably not going to happen, but it would be interesting to instrument a boat and capsize it in various conditions. Many times our assumptions are not correct about the dynamics involved. When Southampton did this with wave induced capsize of monohulls, quite a bit of light was shone to a dark corner of design. Mainly that any monohull can be capsized by a modestly sized wave taken abeam, and that the design of the hull made little difference. A wind induced capsize of a catamaran would be a little harder experiment to devise, but certainly possible. The dynamics are simpler than the wave/monohull case, so maybe some higher powered simulation would yield good results. 

Rob, I wonder if a soft wing with a tail would be the ultimate solution. It would be quite efficient and certainly faster than a sloop rig. The angle of attack is controlled by the tail, and would respond instantly (within perhaps a second) to any gust without crew input. You'd still have to depower in a sharp edged gust, but the forces required to do it are very small and electronics might become practical, mechanics more practical.

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On 3/9/2018 at 6:51 AM, DDW said:

Likewise catamaran capsize is quite rare, and a lot of daily inconvenience in sail trim is a large price to pay for a rare event.

Overall as a sailing type it is rare.

Personally  I love my catamaran and wouldn't own anything else.

Within the cruiser racers, racing, not so.

In the last 6 months in Australia 2 x 50 footers have capsized while racing  . The good bit was it was in shallow, calm water so little damage done.

1 x NSW and 1 in QLD. Both overcome by gusts.

Considering offshore multihull racing in Aus is about as popular as Swine Flue, and boats in the 50 ft range racing are even less popular, then these capsizes are significant.

I have nothing against people tearing around like DICKHEADS ( MEN as Soma says) in the privacy of their own homes. I do have a beef when others are left to pick up the pieces.  Capsizing a lightweight over canvassed catamaran, in the lee of a land mass known for its gusts is BULLSHIT. SELFISH is the term I would use.

Don't involve innocent bystanders when getting your jollies. Get your own "chase boat" and leave your EPIRB at home.

Remember no gear failed causing these capsizes. It is just a case of not enough righting moment/ Not enough crew diligence. 

Alternatively sail with a little seamanship or sort the problem out through  design.

Burying your head in the sand like Soma is not going to do the sport much good long term.

 

image.thumb.png.83c9bbde6e8f8ec892ee89a8390fc4d6.png

 

 

12341305.jpg
 

 

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9 hours ago, harryproa said:
Once boat owners do realise there is an alternative to capsizing when a half decent, easily anticipated gust hits them and their 7 "highly experienced" multihull crew, they might also start to rethink the need for all the other expensive and heavy gear on the boat.  Things like multiple winches, some of them electric with gen sets , batteries and fuel to run them, travellers, complex halyard locks, multiple furlers, carbon and dyneema rigging, mast rams, hydraulics, curved boards, complex instruments, systems and sails requiring 7 crew plus their food and safety gear and time consuming build methods using expensive materials.  Then add on the extra material required to withstand all these loads and the full time crew to look after it all. 
 
Remove and replace that lot with smart solutions, and you end up with a boat that is ~25% of the weight, same sail area, ~10% of the cost, uncapsizable,  2 or 3 crew and  maintenance being a quick look over things before putting to sea and a hose down at the end of the race.     Would it be as fast? The first one wouldn't be, maybe not the second, but speed for offshore multis is a function of sail area, length and weight, so it is only a matter of development.

Wow... I look forward to seeing how your 4,500 kg  66' catamaran that costs $600k lines up with the HH66 :)

M

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17 hours ago, harryproa said:

 

 

 
Once boat owners do realise there is an alternative to capsizing when a half decent, easily anticipated gust hits them and their 7 "highly experienced" multihull crew, they might also start to rethink the need for all the other expensive and heavy gear on the boat.  Things like multiple winches, some of them electric with gen sets , batteries and fuel to run them, travellers, complex halyard locks, multiple furlers, carbon and dyneema rigging, mast rams, hydraulics, curved boards, complex instruments, systems and sails requiring 7 crew plus their food and safety gear and time consuming build methods using expensive materials.  Then add on the extra material required to withstand all these loads and the full time crew to look after it all. 
 
Remove and replace that lot with smart solutions, and you end up with a boat that is ~25% of the weight, same sail area, ~10% of the cost, uncapsizable,  2 or 3 crew and  maintenance being a quick look over things before putting to sea and a hose down at the end of the race.     Would it be as fast? The first one wouldn't be, maybe not the second, but speed for offshore multis is a function of sail area, length and weight, so it is only a matter of development.  

 

7

Enjoy building this multi without carbon or Dyneema. 

Have you ever used a modern halyard lock? Pretty darn simple if you ask me!

 

Also..7 or 8 crew on a 53 footer is nothing! Sure is better than doing a Hobart with 12-15 people on a TP52.

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19 hours ago, DDW said:

Probably not going to happen, but it would be interesting to instrument a boat and capsize it in various conditions. Many times our assumptions are not correct about the dynamics involved. When Southampton did this with wave induced capsize of monohulls, quite a bit of light was shone to a dark corner of design. Mainly that any monohull can be capsized by a modestly sized wave taken abeam, and that the design of the hull made little difference. A wind induced capsize of a catamaran would be a little harder experiment to devise, but certainly possible. The dynamics are simpler than the wave/monohull case, so maybe some higher powered simulation would yield good results. 

Rob, I wonder if a soft wing with a tail would be the ultimate solution. It would be quite efficient and certainly faster than a sloop rig. The angle of attack is controlled by the tail, and would respond instantly (within perhaps a second) to any gust without crew input. You'd still have to depower in a sharp edged gust, but the forces required to do it are very small and electronics might become practical, mechanics more practical.

Good idea on the simulation.  We are collaborating with the Australian Maritime College on a foiling solar powered ferry for use on the Great Barrier Reef. Lots of fun brainstorming with some really bright people.  They have a huge towing tank and (I think) a wind tunnel.  I will suggest this as a topic for them to investigate.  

Soft wings with tails would be safer (and cheaper) than stayed masts and the resulting huge loads and expensive gear to control the sail shapes.  But then so would almost anything.  Lots of smart people are working on it, and making progress, but there is a way to go before the wings are usable and efficient.  And considerably more to get the tails working as effectively as a good crew.  We were going to build an Omer Wing Sail (I am their Aus agent, which is pretty meaningless, but keeps me up to date) for a 50'ter, but the owner ran out of cash so it is on the back burner. It will be interesting to see if the AC does for two surface sails what it did for foils.

 

Trackday/ASP,

will reply to you tomorrow.  

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32 minutes ago, harryproa said:

And considerably more to get the tails working as effectively as a good crew

what is this "tail" you guys are talking about?

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3 hours ago, us7070 said:

what is this "tail" you guys are talking about?

Like the horizontal stabilizer on an airplane, though vertical on a sailboat wing. On an airplane, there is dynamic stability due to the loading and changes in angles of attack of each surface with any disturbance. On an airplane you trim it by setting the difference in angle between wing and tailplane and then it's hands off. The idea is you would have a wing that is free to rotate 360 degrees. A tail hanging off of it is controlled by the "throttle" so to speak, and it controls the rotation of the wing. Set for greater angle of attack for more power. There are a few people working on it (google sailboat wing with tail) and from what I see the tails required are disappointingly large and the whole thing looks ungainly. However it is in its infancy of development. The advantage in this context is that the response to a gust or wind direction change is automatic and the time constant only limited by the rotational inertia of the wing which is small, probably a second or two for a major wind change. There are many variations of the concept using tabs and servo mechanisms, most of which have not been tried experimentally. 

Obviously there are numerous practical difficulties to overcome. It took about 150 years for the sloop rig to reach it's current state of development.

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1 hour ago, DDW said:

A tail hanging off of it is controlled by the "throttle" so to speak, and it controls the rotation of the wing. Set for greater angle of attack for more power.

on an airplane, the horizontal stabilizer is controlled independently of the wing - are you saying that on this rig they are not?

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The tail is the independent control. On an aircraft in stable unaccelerated flight, the horizontal stabilizer is at a fixed angle of incidence relative to the wing. The angle of attack of the wing is not independent, but rather a result of the relationship between load and angle of incidence difference between wing and tail. Same is true of the sailboat rig. You set the angle of incidence of the tail relative to the wing, which in turn sets the angle of attack of the wing (as it is otherwise free to rotate about the hull). When you change the angle of incidence, a new angle of attack of the wing is established at equilibrium. The angle of incidence of the tail relative to the wing is the throttle. 

The stability is similar to setting up a sloop to sail itself. The jib is overtrimmed relative to the main, as the boat heads up the lift on the main drops off faster than the lift on the jib, and it corrects. 

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On 02/03/2018 at 8:07 PM, dcnblues said:

So you're inventing something mechanical? That will be interesting. Tremendous loads on the jib clew, so you'll need something powerful to blow the shackle open. I'm thinking the power source could be a shotgun shell into a steel receiver / release mechanism. Simple, fast, easy enough to trigger and reload. Like a sawstop on a table saw which can stop the blade dead in a hundredth of a second by blowing a block hard into the spinning blade. It needs a certain amount of fast power. 

I agree a mechanical trigger would grant better peace of mind than something electronic, but an electric unit would certainly be cleaner and lighter.

In storm conditions it also wouldn't be that difficult to rig a preventer on the boom with some heavy duty snubbers to keep the boom from slamming into the shrouds. Because the part that I really agree with is that 

Once the gust gets under the bridgedeck, speed is crucial. The wind leverage would need to cut sharply, and anything which took seconds would be too slow. I'm fascinated by this thread. I also think KC375 stated it perfectly just now. But there's also some overlap between racing through a blow and just trying to stay intact in even heavier gale conditions, and it's the later (hypothetically) which interests me.

That’s going fun onboard, not just potentially holding on, getting shot at!! :P

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Ages ago there was a Clam Cleat that we used for a mainsheet release on Stilleto 27's and our Roland 36. They worked pretty good and I started looking around for them for a 50' cat that I'm designing but the big size is nowhere to be found. I guess the ClamCleat people figured out that they were putting themselves into a liability situation and now they only make a little dinky size with the stated use for rudder hold down on dinks and Lasers. Too bad and we may try making our own base from the biggest ClamCleat that is still available.

Image result for clamcleat auto-release rudder cleat

 

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On 07/03/2018 at 12:02 PM, harryproa said:

Sounds feasible, given that it indubitably capsized and we have no other information.   

Is there anything they could/should have done to avoid/prepare for it, apart from DDW's suggestions of faster reactions on the sheets and tiller, luffing hard and a bit more respect to a known wind funnel like Saba?  

Gerald,

Agree about unstayed rigs.  Imagine how things would be if Team Phillips had been built properly, realised it's potential and won The Race.    Cue the usual photos of TP without a bow, which is nothing to do with the staying configuration of the rig.

 

I see the Team Phillips double rig set up mentioned every now and again, from the old pictures they were a huge section and heavier than a single, lightly stayed tube or wing. And you had 2 of them!  

Surely if the advantages were that big, we’d see a lot more sailing around?  Parlier, and his ORMA size catamaran didn’t seem to work out as well as they thought. 

I’m all for innovation, but this one doesn’t seem to work. 

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What a score! I just bought one of the old ClamCleats with the quick release base for cheap. It was know as a CL 226 which is no where to be found on the Clam Cleat website. I did find the anodised aluminum cleat for 1/4" to 1/2" that I can put on this old quick release base if the one that comes with it is too worn out. Going on my 28 foot tri!

s-l1600.jpg

 

s-l1600.jpg

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On 07/03/2018 at 5:27 PM, DDW said:

I actually communicated with Pete Goss about Team Philips' rig before I built my boat. He said the while boat had issues, but the rig worked really, really well. At the time and with the technology they built it, the rig was heavy, but would be much lighter now. 

I am unconvinced ("without independent testing") that the result in a sharp edged gust would be much different due to daggerboard configuration. If the gust rise time is quick enough, the inertia of the hull is all that counts - again this is a dynamic event, and you cannot analyze it only statically. In a soft edged gust, there may be time to accelerate the hulls sideways and slide before the roll. With the sharp gust, the hulls could be sitting on the mythical "frictionless surface" and still go over. I could put some work into calculating the moment of inertial and angular accelerations in roll vs. lateral acceleration but I'm too lazy. Based on experience in both heavy keel boats and light dinghies, in a sharp edged gust the roll happens way before any feeling of lateral acceleration. You are applying the force about 1/3 of the way up the rig - a long way from the CG. That may also be why heavier cats are harder to capsize: they have more static stability but also a lot more roll inertia, making them more gust resistant than the SA/D would imply. 

 

Doesn’t matter how light the rig could be, you still have 2 heavier sections than a stayed section. As well as all the reinforcement of the hulls to support the rigs. 

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On 09/03/2018 at 10:54 PM, overlay said:

Overall as a sailing type it is rare.

Personally  I love my catamaran and wouldn't own anything else.

Within the cruiser racers, racing, not so.

In the last 6 months in Australia 2 x 50 footers have capsized while racing  . The good bit was it was in shallow, calm water so little damage done.

1 x NSW and 1 in QLD. Both overcome by gusts.

Considering offshore multihull racing in Aus is about as popular as Swine Flue, and boats in the 50 ft range racing are even less popular, then these capsizes are significant.

I have nothing against people tearing around like DICKHEADS ( MEN as Soma says) in the privacy of their own homes. I do have a beef when others are left to pick up the pieces.  Capsizing a lightweight over canvassed catamaran, in the lee of a land mass known for its gusts is BULLSHIT. SELFISH is the term I would use.

Don't involve innocent bystanders when getting your jollies. Get your own "chase boat" and leave your EPIRB at home.

Remember no gear failed causing these capsizes. It is just a case of not enough righting moment/ Not enough crew diligence. 

Alternatively sail with a little seamanship or sort the problem out through  design.

Burying your head in the sand like Soma is not going to do the sport much good long term.

 

image.thumb.png.83c9bbde6e8f8ec892ee89a8390fc4d6.png

 

 

12341305.jpg
 

 

What catamaran do you sail again??

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1 hour ago, mad said:

I see the Team Phillips double rig set up mentioned every now and again, from the old pictures they were a huge section and heavier than a single, lightly stayed tube or wing. And you had 2 of them!  

Surely if the advantages were that big, we’d see a lot more sailing around?  Parlier, and his ORMA size catamaran didn’t seem to work out as well as they thought. 

I’m all for innovation, but this one doesn’t seem to work. 

Parlier's double rig had shrouds.

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8 minutes ago, r.finn said:

Parlier's double rig had shrouds.

Thanks for the correction, I’ll find a picture to remind myself. 

It still wasn’t really a success as far as I remember. 

 

5aa47bfa5828f_2003200420VV20Parlier202.thumb.jpg.0a07d82de1d5d0eaab371a6a4935e421.jpg

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1 hour ago, mad said:

Doesn’t matter how light the rig could be, you still have 2 heavier sections than a stayed section. As well as all the reinforcement of the hulls to support the rigs. 

It's all in the materials science. Team Philips wasn't built with the best at the time, and that was nearly 20 years ago. A modern unstayed rig can be competitive in weight with a stayed rig. It will also have a lower center of gravity, though that's more of an advantage in a monohull. The supporting structure is nearly identical to what is required for a stayed rig, so that is a wash. You don't really need two of them, either. 

It's hard to know which is better in performance, because the stayed rig has a 100 year + advantage in development. From experience, my unstayed rig seems competitive upwind with a stayed sloop, off the wind there is no contest. In handling, there is no contest. 

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From a structural point of view, the unstayed rig is always going to be heavier to build:
- ou have huge bending moments requiring a massive "strong point" at the base of the mast
- The mast itself has to handle the bending as well so needs to be significantly stronger (and heavier), even considering the lower compression. It's different on a mono because it's not as stiff so you have less bending and the shroud base is narrower so you have more compression, which moves things in favor of the unstayed option.
- That's why the biplane rig makes sense for an unstayed cat as a way to minimize the extra weight. The bending will be much less on 2 shorter rigs and there is already some significant "hard point" in the hulls where the beam connects, and it might allow a slight reduction in weight of the cross beam without the compression load in the middle (but you sill have to transfer the bending moment from the rigs across and the loads going through waves so I'm not sure I doubt you gain that much... You give up some aspect ratio on the sails so less efficient but lower the center of effort.
- I'm pretty sure the reason no one's done a single unstayed mast on a tri is because the numbers just dont' work due to the huge bending moments at the base of the mast (tall mast and more stability) and extra structure doesn't make sense when you have a nice wide base for a couple shrouds.
- All this to say that I think there's a good reason you don't see it more on racers; if it was faster it would be used all the time as opposed to a few "fringe designs" where it fit the overall picture.

The safety aspect however does make it attractive for cruisers but I'm guessing the "unconventional" aspect is probably what holds it back there (just like proas that on paper seem like a good option for fast cruising but are just too weird for the general public)... Racing proas with conventional boats would provide some serious excitement at mark roundings, and shunting is slower than tacking so these are 2 serious obstacles, none of which should matter for cruisers yet proas remain very rare...

 

Then there's also this, which seems to combine the disadvantages of several different approaches (I'm still looking for what advantages this configuration might have):
trimama_sous_voiles.jpg

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On 3/10/2018 at 4:15 PM, ASP said:

Enjoy building this multi without carbon or Dyneema. 

Have you ever used a modern halyard lock? Pretty darn simple if you ask me!

Also..7 or 8 crew on a 53 footer is nothing! Sure is better than doing a Hobart with 12-15 people on a TP52.

7 or 8 crew is more enjoyable than 15.   2 or 3 is more enjoyable than 7 or 8.    Especially if the boat is set up so the wives, kids or non sailing friends of those 2 or 3 can do the race in comfort, without having to do any work, are not in the way,  in danger, likely to be scared, wet or cold  and don't have to move when they don't want to.  
"carbon or dyneema" referred to the standing rigging.  
If a modern halyard lock meets the requirements below, please let me know. 
13 hours ago, mad said:

Doesn’t matter how light the rig could be, you still have 2 heavier sections than a stayed section. As well as all the reinforcement of the hulls to support the rigs.

 
Plonking unstayed rigs on boats designed for stayed rigs is not optimal.  Design the boat for an unstayed rig and it will be lighter overall, although non bridgedeck cats may require some not very pretty structure to support the mast.  Stayed masts require the entire structure between the traveller, forestay and shrouds to be immensely strong to stop it bending or driving the mast through the bottom.  An unstayed rig requires horizontal support at the deck and keel which is far easier to provide.  
The 15m harryproa in the video at  https://www.youtube.com/watch?v=8chR6DAFjGA weighs 3 and a bit tons/tonnes in cruise trim.  The mast is supported with  2 kgs/4.4 lbs of carbon tow ($US80) at the deck, a ring frame and 2 cedar braces (12" long 2" x 2"/ 300mm x 50mm x 50mmglassed in with 5 kgs of double bias glass. there is no traveller, forebeam, shroud bulkheads or massve main and rear beams.  

We are working on a couple of other attributes of unstayed masts which stayed ones don't have.  1)  It is quite simple to make an unstayed mast telescope, allowing more sail up high in light air and lower centre of gravity and less windage when reefed.  2)  An unstayed mast can have the sail attached to it with hoops.  Done right (which we haven't yet, but are getting close), these place the sail on the lee side of the mast, decreasing the turbulence and reducing the weight, cost and complexity by eliminating the mast track, rcb cars and mast bearings.    Combined, these 2 attributes allow for a larger, stiffer, lighter mast section to be used.  

 

9 hours ago, Airwick said:

From a structural point of view, the unstayed rig is always going to be heavier to build:
- ou have huge bending moments requiring a massive "strong point" at the base of the mast
- The mast itself has to handle the bending as well so needs to be significantly stronger (and heavier), even considering the lower compression. It's different on a mono because it's not as stiff so you have less bending and the shroud base is narrower so you have more compression, which moves things in favor of the unstayed option.
- That's why the biplane rig makes sense for an unstayed cat as a way to minimize the extra weight. The bending will be much less on 2 shorter rigs and there is already some significant "hard point" in the hulls where the beam connects, and it might allow a slight reduction in weight of the cross beam without the compression load in the middle (but you sill have to transfer the bending moment from the rigs across and the loads going through waves so I'm not sure I doubt you gain that much... You give up some aspect ratio on the sails so less efficient but lower the center of effort.
- I'm pretty sure the reason no one's done a single unstayed mast on a tri is because the numbers just dont' work due to the huge bending moments at the base of the mast (tall mast and more stability) and extra structure doesn't make sense when you have a nice wide base for a couple shrouds.
- All this to say that I think there's a good reason you don't see it more on racers; if it was faster it would be used all the time as opposed to a few "fringe designs" where it fit the overall picture.

The safety aspect however does make it attractive for cruisers but I'm guessing the "unconventional" aspect is probably what holds it back there (just like proas that on paper seem like a good option for fast cruising but are just too weird for the general public)... Racing proas with conventional boats would provide some serious excitement at mark roundings, and shunting is slower than tacking so these are 2 serious obstacles, none of which should matter for cruisers yet proas remain very rare...

The mast on the harryproa in the video weighs 120 kgs and is built from carbon and glass.  The boat has a righting moment of 18,000 kgms, the same as a 6 ton 12m/40' cruising cat or tri.  No reason why it would not work just as well on one of them.  60 years ago no one raced cats, because "if they were quicker, everyone would use them".  

Shunting can be  a little slower than tacking, but is less likely to be a screw up.  Mark roundings are no more exciting than they are with tacking cats.  

Proas are slowly catching on as more people start to understand them.  

Trimama, the 3 rigs tri was in the 2 handed Round Britain with us.  Nice guys, they had some good ideas, but were almost as short of money as we were.  Over a third of the entries were multis,  25' to 80'  and few of them looked alike.  Several of them were experimental, but 2/3rds of them finished.  The weather was far harsher than the C600, where less than 15% were multis, none of which could be described as cheap and experimental and only 1/3rd of whom finished.  My point?  The "advantage" of Trimama was that they got to compete in a race against the world's best on a budget boat, talk to like minded loonies and have a cool time doing it.  These days, not so much.

On 3/10/2018 at 8:57 AM, trackday said:

Wow... I look forward to seeing how your 4,500 kg  66' catamaran that costs $600k lines up with the HH66 :)

M


I was referring to Fujin, but happy to oblige for the HH.   I did not mention catamarans.  There are far more cost effective ways of going fast comfortably and safely than cats.  

HH 66 Specifications -
LOA : 20m/66', BOA :8.7m/28.5', Sail area: 217 sqm/2332 sq', Displacement Lightship:17,000 kg/37,479 lb, Draft:1.9m/ 6' -   4.00 m, 13' Payload: 4,000 kg, 8,800 lb

Bruce Number (power to weight, the most reliable means of comparing speed potential, the higher the BN, the faster the boat):  1.4
Wind strength to fly a hull assuming full sail: 20 knots 
Resale loss, $2.3 million dollars after 12 months http://www.yachtworld.com/boats/2017/HH-Catamarans-HH66-3068735/United-States#.WqMYM2Z7FsY

The C60 harryproa http://harryproa.com/?p=1747
LOA: 18m/60′, BOA: 9m/30′, Weight: 4,000 kgs/8,800 lb, Sail Area: 130 sq m/1,075 sq’, Draft: 400mm/18″- 2m/6’8″, Payload: 3,000 kgs/6,600 lbs
Bruce Number (power to weight, the most reliable means of comparing speed potential, the higher the BN, the faster the boat):  1.6
Wind strength to fly a hull assuming full sail: 20 knots 
The first C60, for a live aboard family on a world cruise, is underway in Peru, from where it will be sailed, via Straits of Magellan/Cape Horn, to the Caribbean.  It is a cost plus build, estimated cost $500K, based on progress so far.  There is a waiting list for the next build.  I have no idea what the resale values of cruising harryproa's are as none of the original owners have sold them.  But even if you gave a C60 away after 12 months, the max loss loss is $0.5 million. 

Extending the length (during the build) to 66' would add less than 50 kgs/110 lbs and cost a couple of grand.  

Both boats have similar capsize wind strengths, the harry has a little better power to weight, so is theoretically quicker, probably offset by the H66 sail wardrobe.     The harryproa weight is 24% of the HH, cost is 08%.  


The attached Custom 66 is currently being built in Norway. http://harryproa.com/?p=726  This is a live aboard foam and glass world cruiser/office, for 2 couples.  It is on track for a finished weight around 3 tons.  It is amateur built so costings are not reliable, but pro built, it will be significantly cheaper and faster than the C60.  

I down loaded the following from the HH web page and added  comments on the harryproa solutions I mentioned in my post above:
"Hull, deck and structure are all 100% carbon/foam"

This is apparently required to provide stiffness for the highly tensioned rig, although I suspect it is more to add glamour to the sales brochure.  The harryproa rig is unstayed, with no riggng loads, so can be built with fibreglass. 

"6m/20' long, curved daggerboards are constructed from prepreg carbon", 

Daggerboards are not required on the harryproa as the rudders are over sized and located at 25% and 75% of the length, making the dagger boards redundant.  They kick up in a collision and can be lifted for balance and shallow water resulting in minimum draft of 18 inches  vs 6 feet on the HH which is keel boat territory.  There are no holes below the waterline so no worrying about grounding or hitting floating debris and destroying the boards and rudders and/or ripping a hole in the bottom of the boat.

"Prepreg carbon mast, boom and longeron"

A carbon mast is worth the money, but the small benefits of prepreg vs infused are well outweighed by it's cost and complexity (freezers, heaters, high temp moulds).  A longeron (and forebeam/striker) are not required if there are no headsails.  Nor is any foredeck work or getting up at 2 am in a rain squall to battle with a flogging sail when the furler fails.

"Rigging is all carbon fibre and aramid"

An unstayed mast does not need these.  Nor does it need all the maintenance, careful setting up and tuning.  Install it and forget about it until it needs repainting.  

"Carbon wheels mounted on swinging pedestals allow the helmsman to sit outboard" (in the wind, spray and rain so he can see the sails)

Good idea, harryproas have the same, except the helmsman can comfortably see the sails and is sheltered from the wind in both positions.

"Push button, hydraulic mainsheet controls"

Lousy idea,  complex, heavy and prone to fail compared to the harryproa solution of a self vanging wishbone boom and a lightly loaded sheet on a winch with an auto sheet dump at a predetermined angle of pitch or heel.

"raised helm station"

These are an abomination.  You can't see under the headsail,  get a stiff neck looking at the main, are cut off from the rest of the crew, exposed to the wind and/or looking through a wet windscreen, need to climb up to get in them and have nothing to brace against in a seaway.  The harryproa has the helm in the lee of the cabin rather than behind it so the helmsman is out of the wind with a clear view of the sails and horizon, with the option of ducking into the cabin (with the wheel on it's pivot) if it starts raining.  

"Electric dinghy davits"

Davits put the dinghy weight in the worst possible position (apart from up the mast or hanging over the bow) so it needs to be small and light. Mount it amidships and it can be much bigger and more powerful.  The C60 tender is 7.5m/25′ long, 1.9m/6’2″ wide, with seating for 8 and an outboard from 15-70 hp. 

"Cockpit seating for 6 and a dining table for 7 on a boat that sleeps 8" (although the 2 double bow bunks are unusable in a seaway) is arse about face and not very sociable.  The C60sleeps 6 (plus 2 temporarily),  has dining tables for 8 (plus 8 more if required) and cockpit seating for 30.    The cockpit seating allows a view forward so you don't feel enclosed.

"Forward cockpit/internal helm" 

Only required because a bridge deck catamaran cockpit is such an awful place to sail from.  Not that a forward cockpit is much better in a breeze, according to the Elvis guys.

"Halyard locks"

are a great idea if they also operate at the headboard when the main is reefed (this is important to relieve the horizontal load on the mast track), do not require extra lines to operate them, are fail safe (can be released from the deck if the halyard and release lines are broken or waving in the breeze), maintenance free and cheap.  Harryproa halyard locks meet these requirements, weigh about 200 gr/7 oz and cost about 10 bucks.  

"2 x 80 ho Yanmar diesels with saildrives, 12 kw genset and 200 gallons of fuel to run them"

Sail drives  are notorious for leaking, hitting things, fouling (ropes and growth), maintenance and generally being a pain in the butt.  3 inboard diesels are 3 more major things to maintain and worry about.  The C60 is light and easily driven, so a single large, easily accessible outboard drives the boat at 10 knots, with a small retractable and steerable electric motor under the bridge deck for maneuvering.   It is possible, as well as less smelly and quieter to get by on solar panels and batteries for electric power.    

"84,000 BTU air con"

Maybe in a sticky marina or on the hard but should be unnecessary if the ventilation is good while sailing/anchored.  Cool air from under the bridgedeck, near the water surface, vented through the boat and out the roof works well.   

etc etc.    If you want more examples or a more detailed explanation of these, and don't want to be subjected to the "manly" abuse on this forum, email me at harryproa@gmail.com

I appreciate that this does not cater for different tastes and preferences.  It is simply an example of how winding the spiral towards light, low cost and simple can give the same performance as heavy, complex and expensive.  

Custom67_08.jpg

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12 hours ago, DDW said:

It's all in the materials science. Team Philips wasn't built with the best at the time, and that was nearly 20 years ago. A modern unstayed rig can be competitive in weight with a stayed rig. It will also have a lower center of gravity, though that's more of an advantage in a monohull. The supporting structure is nearly identical to what is required for a stayed rig, so that is a wash. You don't really need two of them, either. 

It's hard to know which is better in performance, because the stayed rig has a 100 year + advantage in development. From experience, my unstayed rig seems competitive upwind with a stayed sloop, off the wind there is no contest. In handling, there is no contest. 

You were referring to team philips, which had 2 rigs, so was I. 

Are there any catamarans with a single unstayed mast?

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3 hours ago, mad said:

You were referring to team philips, which had 2 rigs, so was I. 

Are there any catamarans with a single unstayed mast?

It wasn't clear that you were referring only to Team Philips, and I was speaking more in general. 

I am not aware of any catamaran with a single unstayed mast. The asymmetry would be unusual, but other than the aesthetics, nothing wrong with it. You would not step the mast in the center of the cross beams, but in one hull. I will point out that there is little difference in stress if it was stepped on the cross beams, but the molding work to execute that in a way that the mast could be unstepped would be daunting. Easier to bury it in a hull. 

Airwick mentions that the wide staying base on a cat allows lighter sections to be used compared to a monohull and that is true. The "massive strong point" requires no more structure than you otherwise need for a stayed mast - this is often mistakenly cited by those unfamiliar with the concept. 

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Well if you ever met Cap'n Kirk the designer/builder you would know why. I think it came in pretty heavy. I think Proa who posts here might have sailed on the boat and can provide some details.

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45 minutes ago, Rasputin22 said:

I think Proa who posts here might have sailed on the boat and can provide some details.

I recall reading about the boat, not sailing it.  Not surprised it's heavy.  For a Wyliecat 30-style unstayed rig, "burying" the mast in a hull is a practical requirement.

30a.jpg

Racing catamarans with stays have never had a problem supporting their mast base between the hulls.

IMG_2582.thumb.jpg.41c615e6ab89c25f107bddcc4ac7b3cc.jpg

Systems like the HarborWing tail-drive, and other speculative solutions that require an unstayed mast, are far from being competitive in races like the Caribbean 600.  Going slower might be safer but doesn't win. 

P.S. The Wylie 66:

66b.jpg

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Quote

60 years ago no one raced cats, because "if they were quicker, everyone would use them".  

Shunting can be  a little slower than tacking, but is less likely to be a screw up.  Mark roundings are no more exciting than they are with tacking cats. 

Proa, you are missing my point entirely:

I don't think anyone ever argued that catamarans were too slow to be raced! Well, a few would have for sure but that's not why people weren't racing cats... It's because they "aren't real boats" and were actually banned from racing because they made the monos look bad (Amaryllis)! And we aren't quite over that yet although civilyzed people now agree that the type of boat you want to race is a matter of personal preference rather than performance.

When it comes to racing, "less likely to screw up" is not the main criteria, the option that is faster most of the time is what will get you around the course the fastest and therefore the one that is going to be used (racers assume they can go through a tack without fucking up most of the time...)

The exciting part I was referring to was mixing types of boats following completely different paths around a mark, if you had only proas rounding together it would be fine.

 

As I was saying, I agree with your arguments in a cruising context but they just don't really work for racing. If an unstayed rig was faster overall, the AC 45 would not have had stays... 

 

Quote

My point?  The "advantage" of Trimama was that they got to compete in a race against the world's best on a budget boat, talk to like minded loonies and have a cool time doing it

Not arguing they didn't have fun or a great experience but this isn't an attribute of the design: a "conventional rig" should not have been more expensive or less reliable (probably less expensive considering the complexity of this one) and would have been faster. Irrelevant if you are just in it for the fun of participating but matters if you are trying to win.

 

Quote

The "massive strong point" requires no more structure than you otherwise need for a stayed mast - this is often mistakenly cited by those unfamiliar with the concept.

DDW: I can see that being the case in a hull where you have lots of vertical separation to absorb the bending moment (and where the reduced compression would offset that as well) but if you try to put a unstayed mast on the crossbeam of a racing cat, it will require some serious extra structure to handle the bending (compared to a simple dolphin striker to take the compression). Again, not saying it can't be done, just that it is going to be heavier than other alternatives...

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59 minutes ago, Rasputin22 said:

Well if you ever met Cap'n Kirk the designer/builder you would know why. I think it came in pretty heavy. I think Proa who posts here might have sailed on the boat and can provide some details.

This seems to be proving the point that freestanding rigs don’t work out that well in catamarans, or at least aren’t deemed worth trying to develop. 

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1 hour ago, mad said:

Can’t seem to find anything else about it online. Not too popular for some reason?? 

Let me start off by admitting I'm a confessed boat ho and bottom feeder. I look for the weird and unwanted.

I found the Podcat on CL some time back and on one of my trips south to see family I made arrangements to hook up with the owner in Santa Barbara to have a closer look. I was curious about the claims that it could be taken apart and trailered plus there was no metal fasteners used in it's construction. When I arrived, I wondered how long a boat would have to remain unattended in it's slip to have that amount of birdshit covering her. She had 2 new Honda outboards mounted in the middle of the tramps and a decent fully battened main hiding under "nature's whiteout". As far as the boat itself, it felt like you were inside a prop from a Flintstone movie. The one thing that was cool was the rear window in the aft-cabin which felt like being in a pirate ship. 

I talked the owner into a trial sail in a couple of weeks and said I would bring down my power washer to hose off all the bird doo. The nite I was planning to head south something came up and I put off leaving until the next morning. The next morning as I was filling up the fuel tank on my camper I got a call from the owner of the Podcat asking me where I was. I told him I was going to be late getting down there when he told me to forget coming down at all cuz someone had set the Podcat on fire that nite and it was a total loss.

 Some days later I got a call from a Santa Barbara fire investigator about the fire and my whereabouts the nite of the fire. I told him what I knew and asked if I was being looked at as a suspect. He said no, the only person who sets fire to a boat is it's owner!

I think everyone at the marina referred to her as the star-ship and didn't think too much of her. After the dust settled on the whole affair, it would of been worth it to buy the burned out carcass just to get the transferable end-tie!

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I wouldn't let that one example rule out freestanding spars in catamarans. A rather unconventional builder with questionable design skills to say the least. I think that there were a couple of AeroRig catamarans.

Here is one for sale for a bargain $1.8 mil!

JS 52 AeroRig

Looks like it has shrouds which would run counter to the whole AeroRig but this is from another unconventional (now defunct) builder who might have added them for some reason. Don't see a forestay so I don't know what is going on here. Looks like foreward lower stays so maybe they do the trick. Boat has say unlaunched for some time.

   Here are some comments from Richard Woods about AeroRigs

'

"The disadvantages are: 
The rig is very heavy, leading to more pitching and less load carrying. You probably need to modify the cabin. The minimum "immersion" of mast into cabin is about 1 in 7 ie a 35' high mast needs 5' of bury. Also the cabin has to be wide enough to spread the load. Its usually OK with a conventional bridgedeck cabin (although you may need to add a nacelle). Impossible to fit on an open boat and a bit awkward on a boat with a cuddy like the Savannah.

A smaller sail area, especially in light winds and certainly when sailing downwind. That's because the jib is very small (only 20% of the total area) to maintain the correct balance. You can't motorsail safely to windward with both sails unfurled. It is possible to sail an Aerorigged boat backwards. A nice party trick but about as useful as reverse on a motorbike. But I discovered the hard way that the boat could sail backwards in a strong wind when I thought I was motoring forward. After a narrow shave when going under a bridge I always rolled up the jib before motoring. When reefing the jib must be furled first or the rig unbalances"

 

Image result for AeroRig catamarans

Another example of a clearly unstayed cat with an AeroRig.

Image result for AeroRig catamarans

Image result for AeroRig catamarans

Image result for AeroRig catamarans

   A cruising cat with a deckhouse can provide adequate 'bury' for the mast to effectively cantelever without the use of stays and shrouds.

      Here is a racing cat with a balestron that does us capshrouds and forward lower shrouds to support this balestron stepped on a mainbeam without the neccesary depth of bury.

elf_aquitaine1.jpg

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4 minutes ago, Rasputin22 said:

I wouldn't let that one example rule out freestanding spars in catamarans. A rather unconventional builder with questionable design skills to say the least. I think that there were a couple of AeroRig catamarans.

Here is one for sale for a bargain $1.8 mil!

JS 52 AeroRig

Looks like it has shrouds which would run counter to the whole AeroRig but this is from another unconventional (now defunct) builder who might have added them for some reason. Don't see a forestay so I don't know what is going on here. Looks like foreward lower stays so maybe they do the trick. Boat has say unlaunched for some time.

   Here are some comments from Richard Woods about AeroRigs

'

"The disadvantages are: 
The rig is very heavy, leading to more pitching and less load carrying. You probably need to modify the cabin. The minimum "immersion" of mast into cabin is about 1 in 7 ie a 35' high mast needs 5' of bury. Also the cabin has to be wide enough to spread the load. Its usually OK with a conventional bridgedeck cabin (although you may need to add a nacelle). Impossible to fit on an open boat and a bit awkward on a boat with a cuddy like the Savannah.

A smaller sail area, especially in light winds and certainly when sailing downwind. That's because the jib is very small (only 20% of the total area) to maintain the correct balance. You can't motorsail safely to windward with both sails unfurled. It is possible to sail an Aerorigged boat backwards. A nice party trick but about as useful as reverse on a motorbike. But I discovered the hard way that the boat could sail backwards in a strong wind when I thought I was motoring forward. After a narrow shave when going under a bridge I always rolled up the jib before motoring. When reefing the jib must be furled first or the rig unbalances"

 

Image result for AeroRig catamarans

Another example of a clearly unstayed cat with an AeroRig.

Image result for AeroRig catamarans

Image result for AeroRig catamarans

Image result for AeroRig catamarans

   A cruising cat with a deckhouse can provide adequate 'bury' for the mast to effectively cantelever without the use of stays and shrouds.

      Here is a racing cat with a balestron that does us capshrouds and forward lower shrouds to support this balestron stepped on a mainbeam without the neccesary depth of bury.

elf_aquitaine1.jpg

You’re not convincing me about this. :P

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12 minutes ago, olsurfer said:

Let me start off by admitting I'm a confessed boat ho and bottom feeder. I look for the weird and unwanted.

I found the Podcat on CL some time back and on one of my trips south to see family I made arrangements to hook up with the owner in Santa Barbara to have a closer look. I was curious about the claims that it could be taken apart and trailered plus there was no metal fasteners used in it's construction. When I arrived, I wondered how long a boat would have to remain unattended in it's slip to have that amount of birdshit covering her. She had 2 new Honda outboards mounted in the middle of the tramps and a decent fully battened main hiding under "nature's whiteout". As far as the boat itself, it felt like you were inside a prop from a Flintstone movie. The one thing that was cool was the rear window in the aft-cabin which felt like being in a pirate ship. 

I talked the owner into a trial sail in a couple of weeks and said I would bring down my power washer to hose off all the bird doo. The nite I was planning to head south something came up and I put off leaving until the next morning. The next morning as I was filling up the fuel tank on my camper I got a call from the owner of the Podcat asking me where I was. I told him I was going to be late getting down there when he told me to forget coming down at all cuz someone had set the Podcat on fire that nite and it was a total loss.

 Some days later I got a call from a Santa Barbara fire investigator about the fire and my whereabouts the nite of the fire. I told him what I knew and asked if I was being looked at as a suspect. He said no, the only person who sets fire to a boat is it's owner!

I think everyone at the marina referred to her as the star-ship and didn't think too much of her. After the dust settled on the whole affair, it would of been worth it to buy the burned out carcass just to get the transferable end-tie!

Olsurfer, you said the magic word on that PodCat. Capn Kirk really did have a thing for the whole Star Trek thing and spoke glowing of his 'star ship' creations. I think he must have left the West Coast and has been hidden in the slash pine woods of the Florida Panhandle still building his multihulls. I saw a partially built example on CraigsList recently that probably looked just as bad as the bird shit upon PodCat but in this case had mold, lichens, and Spanish Moss growing on it. Her offered me a bargain price on a pair of 50' 'Tornado style' hulls but I never bothered. Probably what I saw on CraigsList. Loved the fire story, if you had confessed you would probably have been the hero of the marina!

    Found Cap'n Kirk (of Sopchoppy, Fl.) launching this cat ELSEWHERE in 2010.

https://youtu.be/jNNvk-XD1bA

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15 minutes ago, Rasputin22 said:

Convincing about what?

The wisdom of unstayed masts on catamarans, that’s where this all began. 

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1 hour ago, Airwick said:

DDW: I can see that being the case in a hull where you have lots of vertical separation to absorb the bending moment (and where the reduced compression would offset that as well) but if you try to put a unstayed mast on the crossbeam of a racing cat, it will require some serious extra structure to handle the bending (compared to a simple dolphin striker to take the compression). Again, not saying it can't be done, just that it is going to be heavier than other alternatives...

There is pretty much no compression in an unstayed mast (unless a jib is carried). On a monohull, the bury of the mast is about the same distance as the 1/2 beam over which all heeling loads in a stayed rig must be resolved, so the forces and stresses are about the same, though a different direction.

On a cat, let's do the Gedanken experiment: The mast at it's base must be able to withstand the max heeling moment of the boat when a hull lifts. At that point as well, the crossbeam must be able to withstand the max moment applied at the mast step down to the leeward hull. On a stayed rig, the leeward shrouds are slack, and at the mast step, the crossbeam must also be able to withstand the max moment in bending, to lift the windward hull. The moment resistance required of the crossbeam is identical in either case, and they will weigh the same. 

The tricky bit is the full moment connection between the mast and crossbeam through a right angle bend. Molded as a single piece in carbon, this is quite possible without a lot of weight. But to make the mast demountable, there will need to be extra structure and weight that would not be present in a stayed rig.

Another factor may be that on the stayed rig, the bending load can be distributed to the two cross beams by two cap shrouds, to some extent - although the placement of the mast will dominate that. 

The Aerorig is not a good example of lightweight free standing spar construction. I know of a large S&S monohull built with one, the owner junked it for a Composite Engineering braided free standing spar and lost 3000 lbs (!!). It wasn't the concept, the execution was quite heavy. 

It's a little hard to get reliable data on rig weights - designers should know, but perhaps don't actually or are circumspect about it. The mainmast on my boat weighs a little under 700 lbs (including stays, shrouds, spreaders, tangs, etc - of which there are none) and is designed to break at about 4.5M inch-pounds moment.

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Hi Overlay, what was the NSW cat that capsized? And is that a half sunken motor yacht in the background, (was it some kind of storm?) I was aware of Rushour going over but not that one. I hear Rushour will be doing the BtoG in a couple of weeks.

On 10/03/2018 at 8:54 AM, overlay said:

Overall as a sailing type it is rare.

Personally  I love my catamaran and wouldn't own anything else.

Within the cruiser racers, racing, not so.

In the last 6 months in Australia 2 x 50 footers have capsized while racing  . The good bit was it was in shallow, calm water so little damage done.

1 x NSW and 1 in QLD. Both overcome by gusts.

Considering offshore multihull racing in Aus is about as popular as Swine Flue, and boats in the 50 ft range racing are even less popular, then these capsizes are significant.

I have nothing against people tearing around like DICKHEADS ( MEN as Soma says) in the privacy of their own homes. I do have a beef when others are left to pick up the pieces.  Capsizing a lightweight over canvassed catamaran, in the lee of a land mass known for its gusts is BULLSHIT. SELFISH is the term I would use.

Don't involve innocent bystanders when getting your jollies. Get your own "chase boat" and leave your EPIRB at home.

Remember no gear failed causing these capsizes. It is just a case of not enough righting moment/ Not enough crew diligence. 

Alternatively sail with a little seamanship or sort the problem out through  design.

Burying your head in the sand like Soma is not going to do the sport much good long term.

 

image.thumb.png.83c9bbde6e8f8ec892ee89a8390fc4d6.png

 

 

12341305.jpg
 

 

 

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6 hours ago, DDW said:

On a cat, let's do the Gedanken experiment: The mast at it's base must be able to withstand the max heeling moment of the boat when a hull lifts. At that point as well, the crossbeam must be able to withstand the max moment applied at the mast step down to the leeward hull. On a stayed rig, the leeward shrouds are slack, and at the mast step, the crossbeam must also be able to withstand the max moment in bending, to lift the windward hull. The moment resistance required of the crossbeam is identical in either case, and they will weigh the same. 

The tricky bit is the full moment connection between the mast and crossbeam through a right angle bend. Molded as a single piece in carbon, this is quite possible without a lot of weight. But to make the mast demountable, there will need to be extra structure and weight that would not be present in a stayed rig.

DDW, we're talking about 2 different kind of bending here. With the conventional rig, the cross beam is subject to bending from the compression at the mast step (i.e. a point load in the middle of a beam), which is easily and efficiently dealt with by the dolphin striker and stays (or by a thicker beefy beam, which is heavier but doesn't have the bit sticking down hitting waves...)

With a freestanding rig, there is a couple applied at the midpoint of the beam which causes a very different load case (case 3.e vs 1.e in: http://www.me.berkeley.edu/~lwlin/me128/formula.pdf). So even though you don't have the compression you have this highly concentrated load generating a huge couple trying to twist the middle of the beam.

The part I was further talking about was the structure needed to handle the loads from the "bury" of the mast base mentioned above which needs to absorb the full righting moment. This is where really high stresses occur and they get exponentially worse as the length of the bury decreases. With stays you have roughly half the beam to transmit the righting moment vs say a couple of feet of structure for the unstayed mast!

As Richard Woods writes, with a full cabin on the deck there is already some structure there to give you some vertical separation but on an open deck racing cat you would have to build something bulky and heavy, hence putting this in the hull makes a lot more sense from a structural engineering point of view as you have more height to bury the base of the cantilever mast. 

Basically that "tricky bit" you mention is indeed very tricky as it needs handle extremely high loads or be rather large (or both), which is most likely going to make it heavier than "conventional" alternatives...

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This tread developes really good - a lot info to get here. My tri was buildt for Aerorig - that why its so light - but being a wide tri it had shrouds. No big succes - now has wingmast and ordinary boom. To simplify the rig one could have a bigger profile with no streaders- but dont see a unstayed mast even a tri has a strongpoint where that might be possible, but the hight stability and desire for low weight is against it.

But maybe a designed for the task tri with 2 smaller unstayed mast - a cruiser - oceangoing with aft-cabin and mid-cocpit.  

 

But Im really looking forward to see de soft-wing-sail develope in the next AC - that can be the next big thing;

Heres T-30 new Stefan Tørnblom-design where they test a version.

http://sailinganarchy.com/2014/07/23/soft-cell/

 

 

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There are a few misconseptions here.
 
Richard Woods actually wrote about the Aero Rig:  
 
Easy sailing: The sails are always working correctly, whatever point of sail. Maybe it would be better to say the rig works to 95% efficiency all the time. A conventional rig may work to 100% if you're an expert, but only 70% if you're not.
 
He got that right, but the rest of what he wrote about the rig is mostly wrong.  
 
If the rig he sailed with was "very heavy". it was an engineering or build error.  As shown in post 322, they can be quite light.  
If the main has a decent roach, the jib can be large, and it is almost as easy to fly extras as it is on a stayed rig.  I used to fly a spinnaker off mine.
There is no way the boat can sail backwards if the rig is centred and the jib is fre top run on the track.  Same applies to conventional rigs with self tacking jibs.
The bury can be as little as you like, but the loads get up pretty quickly.  The smallest we have done was 12 years ago,  7%, bury on a  35' 3 ton open bridgedeck cat.  The 50' mast was mounted  on the aft side of the main beam.  The boat and rig are still sailing. 
 
AeroRigs were built by Carbospars.  I worked with them in the UK and they were way ahead of their time in mast building.  Way behind in time and money managing.  They built several Aerorigs, all of which were successful.  The last one was a disaster, presumably built when they were already broke.  I presume this is the one DDW's friend had.    One of the Carbospars partners has since been deeply involved with the unstayed masts on Maltese Falcon and the 3 masted "A", both pretty good examples of free standing rigs.
 
Single unstayed masts are not common on cats as the main beam or cabin are not usually far enough forward and most of them won't tack in a seway without backing the jib.  Consequently, a ballestron rig is the best solution, but  they are one step too far for most owners.   A pity as they really de-stress sailing.     Shuttleworth wrote a paper many years ago saying they were not feasible due to the loads.  There have been many boats since which showed this to be wrong, but it was accepted as gospel for a while.  
 
The loads on a boat and a mast are the same regardless of stayed or unstayed.  What is different is that stayed masts with travellers or tight luffed foresails load the entire boat in bending which is hard to resist,.  Unstayed masts load the area around the mast at the deck and heel in tension, which is easy to resist.  see post 322 for how little material is required.
 

Airwick,

Sorry to miss your point.  I got a bit excited about someone saying cruisng proas make sense.  ;-)  

Shunting used to be about sailing onto a reach, dropping one jib, pulling up another, raising one rudder, lowering the other and rotating the  boom through 180 degrees  and sheeting it on hard with a 4:1mainsheet.    Harryproas have no jibs, rudders which work as well as NACA0012 sections in both directions and self vanging mains with 1:1 sheets.  You dump the main sheet(s) and pull it in with the new sheet, luffing hard using both of the fore and aft rudders to get onto the new course.  As the race boats are so light, they stop and start very quickly.  They would not be an issue at a top mark in a mixed fleet.  

Fast boats are about weight, sail area/RM and length.  A proa does these better than a cat or tri.    The small loss of distance from shunting is more than overcome by the better speed the rest of the time.  Yet no one races proas in ocean races.  And as the race fleets get more and more into the big bucks range, the boats perform so well that an untried boat which is say 10% faster because of it's type, is left behind because it does not have the same level of gear and expertise.

Amarylis was not banned.  There are numerous threads on Boat Design.net quoting many sources to show this. 

The AC45's have rules requiring stayed rigs.  As DDW says, stayed racing rigs have 100+ years of development time over unstayed ones.  

The Trimama guys, along with me and a few of the others were in it to try new ideas. Where we finished was incidental, although winning (or finishing in my case) would have been nice.   Once you have raced in a boat of your own design, with ideas no one else has tried, it is pretty boring racing on a conventional boat.  

Seagul,

Nice looking rig, but symmetric wings are pretty poor performers.  Some big names involved, though.  What has happened to the boat since 2013?  

Unfortunately, the AC boats look like having a D section mast with a 2 surface sail.  I don't doubt that they will improve it, but there are already a couple of pretty good examples of this.  Heru Sails in Italy  and the guys in Perth to name 2.  

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Symmetric wing? - its balanced but not symmetric? I tried to make contact with them some days ago. 

 

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Rob will probably argue against this but here's a problem with proas on short courses:  every proa carries negative velocity into a tack and they all have to come out of a tack (upwind shunt) on a reach.  No proa can tack from 45 degrees to 45 degrees without making a concession to leeward that is far greater than what a non proa could achieve.  Proas have to be slammed into reverse ,or at least brought to a complete stop, every time they shunt, making them far less efficient to maneuver than a standard sailboat, regardless of the rigging options.  They just come out of tacks at far from optimal angles.  I see no way around this.

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9 hours ago, Airwick said:

DDW, we're talking about 2 different kind of bending here. With the conventional rig, the cross beam is subject to bending from the compression at the mast step (i.e. a point load in the middle of a beam), which is easily and efficiently dealt with by the dolphin striker and stays (or by a thicker beefy beam, which is heavier but doesn't have the bit sticking down hitting waves...)

With a freestanding rig, there is a couple applied at the midpoint of the beam which causes a very different load case (case 3.e vs 1.e in: http://www.me.berkeley.edu/~lwlin/me128/formula.pdf). So even though you don't have the compression you have this highly concentrated load generating a huge couple trying to twist the middle of the beam.

The part I was further talking about was the structure needed to handle the loads from the "bury" of the mast base mentioned above which needs to absorb the full righting moment. This is where really high stresses occur and they get exponentially worse as the length of the bury decreases. With stays you have roughly half the beam to transmit the righting moment vs say a couple of feet of structure for the unstayed mast!

As Richard Woods writes, with a full cabin on the deck there is already some structure there to give you some vertical separation but on an open deck racing cat you would have to build something bulky and heavy, hence putting this in the hull makes a lot more sense from a structural engineering point of view as you have more height to bury the base of the cantilever mast. 

Basically that "tricky bit" you mention is indeed very tricky as it needs handle extremely high loads or be rather large (or both), which is most likely going to make it heavier than "conventional" alternatives...

These are not different kinds of bending, they are pure moment and exactly the same. Isolate your thinking for a minute to just the beam to the leeward of the center. To support the windward hull out of the water, the beam is in pure bending moment, that moment is approximately 1/2 * beam * displacement. How the mast is supported is irrelevant to that moment. In the stayed case, the moment is applied by a couple between the mast butt and the windward chainplate, and on unstayed mast it is the full moment connection between mast and beam. But just to leeward of the mast butt the crossbeam has exactly the same forces in it. Run the numbers from your Roark's Formulas citing, you will see that they are the same. 

The stresses do not get exponentially worse with decreased bury, they get linearly worse. The bending stress never goes above the entire overturning moment, which the mast section already must resist. Therefore the section required of the beam is no larger than the mast section. With stays you have 1/2 the beam to APPLY the bending moment to the beam, this reduces (to zero) the bending moment the mast must withstand - but the beam must resist all the bending moment, the stays do nothing for it. Without stays you apply the bending moment directly through a moment connection and again the maximum stress is identical in the two cases.*

Suppose we had a formable material like steel. Construct a section of it that will resist the heeling moment required, now bend it 90 degrees at the mast step and run it to the leeward hull. The section is the same in the bottom few feet of mast and over to hull (it could be tapered up the mast). This will do everything that is required, though you will need to weld a leg on it for the other hull of equal section if you want to tack. Now mold that in carbon. 

Very few cats (no offshore ones I can think of, even racing ones) have dolphin strikers and stays under the main beams. You see that in the forward beam that supports the forestay. The main beams are universally of sufficient section to be cantilever. With a bridge deck cabin, the beams tend to have substantial depth, easily enough to make the moment connection. One that is disconnectable for unstepping the mast would have some high stress concentrations in the fastenings but certainly it can be done. If you were willing to have a dolphin striker and dolphin stays, the reduction in moment stresses in the main beam would be identical whether you had a stayed or unstayed mast.

The stresses in a cantilever mast are different, it takes some time to wrap your head around it.  

*In reality, considerably less for the unstayed mast, because it will have no additional compression loads from the jibstay which must be resolved in bending of the main beam. 

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4 hours ago, r.finn said:

Rob will probably argue against this but here's a problem with proas on short courses:  every proa carries negative velocity into a tack and they all have to come out of a tack (upwind shunt) on a reach.  No proa can tack from 45 degrees to 45 degrees without making a concession to leeward that is far greater than what a non proa could achieve.  Proas have to be slammed into reverse ,or at least brought to a complete stop, every time they shunt, making them far less efficient to maneuver than a standard sailboat, regardless of the rigging options.  They just come out of tacks at far from optimal angles.  I see no way around this.

Absolutely - and then there are the rules implications if in close quarters with other boats - klusterfuck doesn't even begin to describe it

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9 hours ago, r.finn said:

Rob will probably argue against this but here's a problem with proas on short courses:  every proa carries negative velocity into a tack and they all have to come out of a tack (upwind shunt) on a reach.  No proa can tack from 45 degrees to 45 degrees without making a concession to leeward that is far greater than what a non proa could achieve.  Proas have to be slammed into reverse ,or at least brought to a complete stop, every time they shunt, making them far less efficient to maneuver than a standard sailboat, regardless of the rigging options.  They just come out of tacks at far from optimal angles.  I see no way around this.

No argument from Rob about the problem.     But, as with everything on proas, there are solutions if you look outside the square.

The biggest reduction in distance lost is from fore and aft rudders which steer together to alter course far quicker than stern hung rudders.   If they are also bidirectional, (ie do not need to be rotated), the helm movement is minimal,  about the same as required to tack a cat.     "Slamming into reverse" is  exactly what happens when a 1:1 sheet is dumped and the new one pulled on.  The boat stops like it hit a wall, starts moving in the new direction and luffing (from the sail force as well as the rudders) immediately.    There is no measurable loss of distance to leeward, assuming the rudders are oversize and there is no daggerboard to stall.   Done properly, it is faster than a tack.  The sail is not moving the boat for a split second, whereas on a tack, the sail  is stalled or flapping for most of the manoeuver.

Solo, I could shunt my 10m/33' proa with one directional rudders in about 10 seconds from sheet dump to full speed and on course on the new tack.  With bidirectional rudders, crew and practice it would be way less.

The higher speed potential of a proa more than offsets the small loss from shunting, particularly as the majority of non beach cat  cats try to sail one tack beats as they lose so much time tacking.   The bigger the headsail, the more they lose.    It would certainly not be a worry on an ocean race.  

The fastest shunting rig is a kite.  No boat tacks as fast as a properly set up kite boat shunts.  There have been a few reversible sails which do it nearly as fast.  

Proas are at more of a disadvantage shunting downwind, which is slower than gybing.  There are a number of solutions, including deployable brakes (I have tested this using  a bucket with some success), crew movement (weight aft and inboard to lift the ww hull and the lw hull bow) and sheeting on the front sail  before the aft sail on a schooner to speed the turn.  I am pretty sure that if some keen racers looked at it, downwind shunts would speed up a lot.   

Shunting is not "inefficient".  The ability to sail in either direction is useful at the race start and in some crowded scenarios.  And it is by far the quickest and most direct way to a man overboard. 

Christian,

What specific rules are you referring to?  Please describe a situation where a shunting boat vs a tacking boat would be a clusterfuck, or that the rules as written would not establish who has rights.   

 

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I know it's a thread drift, but we've been experimenting a bit on Jzerro with short tacking.  As we go into the tack, we lift both rudder completely, ease main completely while furling the jib, then we sheet the main in on new stern which immediately rounds the new bow into the wind.  As that's happening we unfurl the new jib and then lower the new rudder.  During the process the windward dagger board is down reducing drift and allowing the boat to pivot on it while the rudders are up.  These tacks show the least loss, but are still far less efficient than pushing a bow through head to wind.  The key seems to be lifting both rudder and quickly sheeting the main on the new stern so the main hull rotates to weather on the daggerboard's axis. Otherwise you'd have to steer the boat to weather with big leeward losses.  I could see it working well on a cat rigged Harry if the rudders could lift and drop easily.

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3 hours ago, harryproa said:

.    There is no measurable loss of distance to leeward, assuming the rudders are oversize and there is no daggerboard to stall.   Done properly, it is faster than a tack.  The sail is not moving the boat for a split second, whereas on a tack, the sail  is stalled or flapping for most of the manoeuver.

 

The above is not fact.  Download raceqs.com and we can compare our proa tacks to a beach cat.  Just based on the tracks it would be pretty obvious which of the three boats is not a proa.  We should show a track with 5 tacks per boat.  Game?

You are correct about kites though.  Kiteboards are the most proven and popular proas.

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9 hours ago, harryproa said:

No argument from Rob about the problem.     But, as with everything on proas, there are solutions if you look outside the square.

The biggest reduction in distance lost is from fore and aft rudders which steer together to alter course far quicker than stern hung rudders.   If they are also bidirectional, (ie do not need to be rotated), the helm movement is minimal,  about the same as required to tack a cat.     "Slamming into reverse" is  exactly what happens when a 1:1 sheet is dumped and the new one pulled on.  The boat stops like it hit a wall, starts moving in the new direction and luffing (from the sail force as well as the rudders) immediately.    There is no measurable loss of distance to leeward, assuming the rudders are oversize and there is no daggerboard to stall.   Done properly, it is faster than a tack.  The sail is not moving the boat for a split second, whereas on a tack, the sail  is stalled or flapping for most of the manoeuver.

Solo, I could shunt my 10m/33' proa with one directional rudders in about 10 seconds from sheet dump to full speed and on course on the new tack.  With bidirectional rudders, crew and practice it would be way less.

The higher speed potential of a proa more than offsets the small loss from shunting, particularly as the majority of non beach cat  cats try to sail one tack beats as they lose so much time tacking.   The bigger the headsail, the more they lose.    It would certainly not be a worry on an ocean race.  

The fastest shunting rig is a kite.  No boat tacks as fast as a properly set up kite boat shunts.  There have been a few reversible sails which do it nearly as fast.  

Proas are at more of a disadvantage shunting downwind, which is slower than gybing.  There are a number of solutions, including deployable brakes (I have tested this using  a bucket with some success), crew movement (weight aft and inboard to lift the ww hull and the lw hull bow) and sheeting on the front sail  before the aft sail on a schooner to speed the turn.  I am pretty sure that if some keen racers looked at it, downwind shunts would speed up a lot.   

Shunting is not "inefficient".  The ability to sail in either direction is useful at the race start and in some crowded scenarios.  And it is by far the quickest and most direct way to a man overboard. 

Christian,

What specific rules are you referring to?  Please describe a situation where a shunting boat vs a tacking boat would be a clusterfuck, or that the rules as written would not establish who has rights.   

 

Are you on drugs?

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On 3/12/2018 at 12:55 PM, DDW said:

These are not different kinds of bending, they are pure moment and exactly the same. Isolate your thinking for a minute to just the beam to the leeward of the center. To support the windward hull out of the water, the beam is in pure bending moment, that moment is approximately 1/2 * beam * displacement. How the mast is supported is irrelevant to that moment. In the stayed case, the moment is applied by a couple between the mast butt and the windward chainplate, and on unstayed mast it is the full moment connection between mast and beam. But just to leeward of the mast butt the crossbeam has exactly the same forces in it. Run the numbers from your Roark's Formulas citing, you will see that they are the same. 

The stresses do not get exponentially worse with decreased bury, they get linearly worse. The bending stress never goes above the entire overturning moment, which the mast section already must resist. Therefore the section required of the beam is no larger than the mast section. With stays you have 1/2 the beam to APPLY the bending moment to the beam, this reduces (to zero) the bending moment the mast must withstand - but the beam must resist all the bending moment, the stays do nothing for it. Without stays you apply the bending moment directly through a moment connection and again the maximum stress is identical in the two cases.*

Suppose we had a formable material like steel. Construct a section of it that will resist the heeling moment required, now bend it 90 degrees at the mast step and run it to the leeward hull. The section is the same in the bottom few feet of mast and over to hull (it could be tapered up the mast). This will do everything that is required, though you will need to weld a leg on it for the other hull of equal section if you want to tack. Now mold that in carbon. 

Very few cats (no offshore ones I can think of, even racing ones) have dolphin strikers and stays under the main beams. You see that in the forward beam that supports the forestay. The main beams are universally of sufficient section to be cantilever. With a bridge deck cabin, the beams tend to have substantial depth, easily enough to make the moment connection. One that is disconnectable for unstepping the mast would have some high stress concentrations in the fastenings but certainly it can be done. If you were willing to have a dolphin striker and dolphin stays, the reduction in moment stresses in the main beam would be identical whether you had a stayed or unstayed mast.

The stresses in a cantilever mast are different, it takes some time to wrap your head around it.  

*In reality, considerably less for the unstayed mast, because it will have no additional compression loads from the jibstay which must be resolved in bending of the main beam. 

DDW: +1 for a well communicated explanation, it makes great sense.  There is a relevant article on the (somewhat old now) 'catamaran concepts' blog with a diagram that I think is well aligned with above.    https://catamaranconcepts.com/2013/08/27/mastload/

I do have a question though, there must be a difference in a stayed vs unstayed mast at the beam/mast connection, yes?  It is the difference between a pinned connection and a cantilevered connection as the latter is required to carry the "full moment connection between mast and beam".  And at this connection you are applying that moment over shorter lengths than the mast/stay/beam triangle.

 

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On 3/12/2018 at 9:55 AM, DDW said:

Suppose we had a formable material like steel. Construct a section of it that will resist the heeling moment required, now bend it 90 degrees at the mast step and run it to the leeward hull. The section is the same in the bottom few feet of mast and over to hull (it could be tapered up the mast). This will do everything that is required, though you will need to weld a leg on it for the other hull of equal section if you want to tack. Now mold that in carbon. 

Ok,
I think I see what you are getting at with this example regarding the bending moment on the beam, it's a bit of a mindfuck isn't it?... You would need some sort of structure to distribute the point loads at the mast/beam connection but I can see how it wouldn't necessarily have to be that big and heavy so I'm with you now (and yes, the load increase is linear not exponential)...
Another thing that is worth pondering from that is that visualizing the typical self supported cat crossbeam (i.e. without a dolphin striker) and turning into a mast makes for a seriously fat mast (even considering that it will taper down)!

I wonder if anyone's ever tried doing a canting unstayed rig? If you had a pivot on top of the beam and the "bury" of the of the mast extending down, you could use some beefy tackle (or hydraulics) to connect that point to the ends of the beam and up with a geometry like a dolphin striker and that could reduce the bending on the main beam (but would add a pile of compression)

Large offshore cats don't have dolphin strikers but a lot (most?) of lighter weight "coastal" ones do: ie all the supersize beachcats (extreme 40, formula 40, GC32, AC 72/45, etc...) the M32 being the only exception I can think off right now. 
 

Now that's a pretty good thread drift!

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15 minutes ago, Airwick said:

I wonder if anyone's ever tried doing a canting unstayed rig? If you had a pivot on top of the beam and the "bury" of the of the mast extending down, you could use some beefy tackle (or hydraulics) to connect that point to the ends of the beam and up with a geometry like a dolphin striker and that could reduce the bending on the main beam (but would add a pile of compression)

Yes, Dick Newick tried this in the mid 70's, (without the tackle or hydraulics) to cant a proa rig fore & aft to achieve balance. He later put an aero-style rig on the boat. He tried lots of unstayed masts on multihulls, including Balestrom and aero rigs, but told me that he was very disenchanted with unstayed masts on multihulls.

Besides being able to dump the main sheet and a few other small advantages, I am not at all attracted to unstayed masts for multihulls. Maybe when I'm geriatric (coming soon) it will make more sense to me, but I doubt I'd be able to afford one (or two).

Rob Denny is the only person on earth who claims that they are home-buildable and inexpensive, (but he also says that his boats are un-capsizable).

I have done a lot of work with very high end composites, but building a reliable mast for sailing offshore is beyond my skill level. Buying a decent free-standing mast is very expensive for a reason; it takes a hell of a lot of carbon and it has to be done right if your life is going to depend on it.

Putting one in a multihull not only adds huge loads to the mast, but huge loads to the boat itself. Why do that when a multihull provides a wide staying base (drastically reducing compression loads on the mast, wires, and fittings compared to a monohull). I don't get why anyone would want to use an unstayed mast in a multihull and I think it's no surprise that almost nobody else does either. 

 

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Yeah, when you think about it a wire or Dux shroud at that sort of staying angle you get on a cat or tri is pretty hard to beat as Russ says. No point and making things any harder than they need to be.

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4 hours ago, Zero Gravitas said:

I do have a question though, there must be a difference in a stayed vs unstayed mast at the beam/mast connection, yes?  It is the difference between a pinned connection and a cantilevered connection as the latter is required to carry the "full moment connection between mast and beam".  And at this connection you are applying that moment over shorter lengths than the mast/stay/beam triangle.

On a cat with a stayed mast, the mast butt connection is almost invariably pin ended, that is, free to rotate in any axis but not translate. It can carry shear and thrust but not moment. An unstayed mast must have a fixed connection, constrained from rotation or translation in any axis. The section of material required is no larger than the section of mast immediately above. In reality it is more complex than that, as stress flow concentrations around the bends and fasteners must be considered, but it isn't rocket science anymore - cantilevered composite connections like this are commonplace (and reliable) in composite aircraft, wind turbines, helicopter blades, etc. On a modern sailplane with a carbon spar for example, the 25 meter span wing resolves all the moment over two pins about 16" apart, intended to assemble/disassemble each day it is flown. 

3 hours ago, Airwick said:

Ok,
I think I see what you are getting at with this example regarding the bending moment on the beam, it's a bit of a mindfuck isn't it?... You would need some sort of structure to distribute the point loads at the mast/beam connection but I can see how it wouldn't necessarily have to be that big and heavy so I'm with you now (and yes, the load increase is linear not exponential)...
Another thing that is worth pondering from that is that visualizing the typical self supported cat crossbeam (i.e. without a dolphin striker) and turning into a mast makes for a seriously fat mast (even considering that it will taper down)!

The beams on a cat have also to resist many other hydrodynamic loads and are already likely to be far stronger than is needed  for the mast. Dolphin struts and stays can spread the loads to a wider area, at the expense of trading bending for compression, just as shrouds do for a mast. 

3 hours ago, Russell Brown said:

Yes, Dick Newick tried this in the mid 70's, (without the tackle or hydraulics) to cant a proa rig fore & aft to achieve balance. He later put an aero-style rig on the boat. He tried lots of unstayed masts on multihulls, including Balestrom and aero rigs, but told me that he was very disenchanted with unstayed masts on multihulls.

----

Putting one in a multihull not only adds huge loads to the mast, but huge loads to the boat itself. Why do that when a multihull provides a wide staying base (drastically reducing compression loads on the mast, wires, and fittings compared to a monohull). I don't get why anyone would want to use an unstayed mast in a multihull and I think it's no surprise that almost nobody else does either. 

 

Dick Newick lived in the dark ages of materials science. In 20 years we will be saying that now was the dark ages of materials science. Unstayed masts really have only become practical with carbon fiber and some advanced molding techniques, and is still primitive compared to where it is headed. 

There are no huge loads added to the boat, those loads are about the same either way. The huge loads on the mast are due to the wind - they are there no matter how you engineer structure to deal with them. You either have huge compression/tension loads or huge bending loads. Material science advances are making it easier each year to deal with them as a bending load, while not helping as much in compression loads. The cost for a professionally built carbon free standing mast is currently at least competitive, and more likely less than a professionally built carbon stayed rig - the tube costs more, but added to all the other hardware needed on the stayed rig the total is less. This was certainly true on my boat.

The wide staying base isn't really all that different on today's boats - a 40' cat might have 20' beam, but a 40' monohull will have a 14' beam. The compression reduction in the stayed mast will be 30% on the cat - a welcome, but not overwhelming reduction. 

Having said all that, I agree with Russell and Rasp that putting an unstayed mast in the middle of a cat at this moment in development seems to skip over the more obvious conventional solution. In a trimaran, or in one or both hulls of a cat it makes more sense, if full advantage is taken of the benefits. 

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Im attracted to the efficency and simplyness of an unstayed rig - we will change all stays to fiber soon - and I see there so many meters of ropes standing in the air making weight and drag. I think the next development will be soft-wings on unstayed masts - Like the T-30 over - a balanced mainsail makes a lot of sence.   

 

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Airwick.

We intended to use a canting (and raking) rig on the Volvo Proa, particularly for lake sailing where a maximum length boom would have provided too much weather helm.  volvoproa.pdf

I leave it to the pedants to decide whether this rig is stayed or not.  

Testing the canting is one of the things on the to do list for the foiling harry below.  

8 hours ago, r.finn said:

The above is not fact. 

That is not very polite.  It may not be a "fact" for your boat where you have to lower and raise rudders and jibs, and rely on leeway and subsequent drag from the daggerboard to rotate the boat, but I can assure you it works well on a boat where there is nothing to raise and lower and the rudders work as foils to rotate the boat.  

Happy to record some tracks/make a movie when i get some time.  However,  my boat is in pieces while I investigate foiling

and this has been put on hold while I do some materials testing for the 24m sailing cargo/ferry which we will be building for Pacific islands use next year. http://harryproa.com/?cat=51    

Christian,

No, I am not on drugs.  I have spent 20+ years developing proas, experimenting with every configuration I (and many other interested people) could come up with.  The results are what I posted.       

I presume you could not come up with a scenario to support your contention that  "proas would be a clusterfuck racing with conventional boats"?   

HP Cargo Ferry 009.jpg

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And there you have a disandvantage with the unstayed rig - it cant easy be canted.....

 

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Seagul, (post 344)

What I meant is the rig appears to be uncambered, which is not fast. 

You can cant an unstayed rig by moving the bottom of the mast.  Needs a spherical deck bearing, but most big rigs have these anway.   Not a lot more difficult than canting a stayed rig.

Gerald,

The capsize in NSW was actually Big Wave Rider (I think) in Hobart.

9 hours ago, Russell Brown said:

Yes, Dick Newick tried this in the mid 70's, (without the tackle or hydraulics) to cant a proa rig fore & aft to achieve balance. He later put an aero-style rig on the boat. He tried lots of unstayed masts on multihulls, including Balestrom and aero rigs, but told me that he was very disenchanted with unstayed masts on multihulls.

Peculiar, given that the multihull that put him on the map (Cheers) had unstayed masts.  Materials, build methods and understanding of what is involved have all progressed since the 70's.  When I spoke to Dick about the unstayed mast we were putting in the prototype bimaran (http://www.nzherald.co.nz/marine/news/article.cfm?c_id=61&objectid=3198180) in 1998 he thought it (mast and boat) was a great idea and could not see any reasons why it wouldn't work.   He was right, the mast worked a treat and the boat won the RINA Design Competition.  We built that mast from prepreg in a steel mould.  6 atms pressure and 110C/250F.  Materials and methods certainly have changed.

 
9 hours ago, Russell Brown said:

Besides being able to dump the main sheet and a few other small advantages, I am not at all attracted to unstayed masts for multihulls. Maybe when I'm geriatric (coming soon) it will make more sense to me, but I doubt I'd be able to afford one (or two).

Pretty sure Fujin and the Atlantic cats which capsized would not consider dumping the main a "small advantage"  

There are others:

You are not relying on a whole lot of small pieces, any one of which can break and cause the mast to fall down. For example, the $10 piece of stainless in the rig that caused your boat to capsize.

The rigging does not need constant tuning, checking, maintenance or replacement of fittings and stays.   And you do not worry about it when the breeze gets up. 

The boat can be cheaper and lighter, with a lower cog and less windage.  See Richard Wood's comment about being right 90% of the time vs 70% of the time for a stayed rig without expert trimming.

The sails can be hoisted, reefed and lowered on any point of sail and the boat can be stopped while this is done. 

The masts can be bench tested, and if they pass, you can be confident they will not break in use.    

9 hours ago, Russell Brown said:

Rob Denny is the only person on earth who claims that they are home-buildable and inexpensive, (but he also says that his boats are un-capsizable).

 

He's not.  All the people who have built them think so too. As do the Kelsall owners who have built theirs, including a biplane rigged 70'ter (Cool Change).  

Have a look through  www.harryproa.com, where there are photos of at least 2 x 66'ters, 3 x 50'ters and 2 x 40'ters with masts built by unqualified or home builders, plus a bunch of others I don't have pictures of.     And many beams, booms and sundry tubes built the same way.   None have broken, apart from my experimental sfforts .  Many samples have been tested, and met specs.    

If you quote me, do so in context.  Uncapsizable was referring to the sheet dump mechanism.  Sorry if this was not clear.

9 hours ago, Russell Brown said:

I have done a lot of work with very high end composites, but building a reliable mast for sailing offshore is beyond my skill level. Buying a decent free-standing mast is very expensive for a reason; it takes a hell of a lot of carbon and it has to be done right if your life is going to depend on it.

The masts on the 50'ters above weigh 120 kgs/264 lbs, of which 60 kgs is carbon at $30/kg ($1,800), 40 kgs is resin ($500) and  20 kgs is glass ($200).  Plus a couple of hundred bucks of consumables (mdf, formica, vac bag).  Near enough $3,000.   That is a  17m/57' unstayed mast suitable for a 6 ton, 8m/26' wide cat which would also need a hundred bucks worth of carbon tow and resin to beef up the cabin top and the floor.  

Building stayed masts is harder than building unstayed (smaller moulds, more local reinforcing), but we have sold plans for a few of these as well.   

"Doing it right" is no more diffcult than any other part of boat building. You just need an open mind, an awareness of what is involved and a decent set of plans.  

9 hours ago, Russell Brown said:

Putting one in a multihull not only adds huge loads to the mast, but huge loads to the boat itself. Why do that when a multihull provides a wide staying base (drastically reducing compression loads on the mast, wires, and fittings compared to a monohull). I don't get why anyone would want to use an unstayed mast in a multihull and I think it's no surprise that almost nobody else does either. 

 

DDW explained about the loads and I explained about how little material is required to resist them and why.  Instead of incorrect generalisations,  tell us where you think we are wrong.    

Your wider staying base logic is flawed.  A wider staying base means smaller fittings, which are just as likely to break as bigger fittings on a narrow base.   Or are you saying you use oversze fittings?   The best way to ensure fittings don't break is to not have them,

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2 hours ago, harryproa said:

Your wider staying base logic is flawed.  A wider staying base means smaller fittings, which are just as likely to break as bigger fittings on a narrow base.   Or are you saying you use oversze fittings?   The best way to ensure fittings don't break is to not have them,

My logic is flawed? And yes, you have promoted your boats with some pretty optimistic marketing, including calling them "un-capsizable", which is utter bullshit.

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That is true Rob, you did market it as uncapsizable in a Bucketlist animation.  Also it's not Russell's logic.  Every modern performance multihull uses that same logic.

 

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3 hours ago, overlay said:

While the establishment fights for the status quo another multi is overcome by a gust and requires rescue.

https://www.sunshinecoastdaily.com.au/news/four-rescued-as-33-foot-vessel-capsizes-south-of-c/3358610/

 

Water police were forced to rescue four people after their trimaran capsized yesterday in North Brisbane.
Water police were forced to rescue four people after their trimaran capsized yesterday in North Brisbane. QPS

If only the facts could be shared on this. A very sad clusterfuck. Suffice to say shared ownership, newbies, no pfd's, weather (30 knots plus squalls) so foul I had to sit on my sailboard (in protected waters with a 4.5 sqm sail) to stop it disappearing down the beach, and one of the clear pics of this boat showing a submerged sail deployed from the bowsprit, dinghy on the nets.....

A lot of angry guys down here looking at our muppet-indexed insurance premiums going up.

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On 3/13/2018 at 5:02 PM, Christian said:

Are you on drugs?

Christian, just use the same filter I do. Take every claim he makes that uses the words could, should, or would, and throw them in the garbage can. Everything else he says is usually good reading. 

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12 hours ago, plywoodboy said:

If only the facts could be shared on this.

Does this mean the facts are known but can't be shared?  If so, why not?   

Monkey,

Great idea if you only want to know what has already happened.  Not so good if you want to discuss ideas and contribute to what might be possible.  Or I could do what everyone else does and post ideas and suppositions as facts.    

Russ and Ryan,

Like I said, the uncapsizable was in relation to the sheet dumping device.  I also apologised for writing something that someone wanting to undermine me might misinterpret.  For what it is worth, used properly, the sheet dump device i described would make the boat uncapsizable in normal use.  If you disagree with this, please explain why so I can alter it before installing it.

Nothing about how wrong Russ was re: the ease of building masts, their costs or the other advantages of unstayed masts?

A wider staying base reduces the loads a little, not the potential for breakages.  This may not seem logical to you and other multihull sailors, but it is reality.    And as the Fujin story (actually DDW's interpretation of the Fujin story, we still have not heard from any one on board)  showed, the "logic of every modern performance multihull" is not necessarily correct.  

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13 hours ago, plywoodboy said:

If only the facts could be shared on this. A very sad clusterfuck. Suffice to say shared ownership, newbies, no pfd's, weather (30 knots plus squalls) so foul I had to sit on my sailboard (in protected waters with a 4.5 sqm sail) to stop it disappearing down the beach, and one of the clear pics of this boat showing a submerged sail deployed from the bowsprit, dinghy on the nets.....

A lot of angry guys down here looking at our muppet-indexed insurance premiums going up.

Peter - This thread took such a strange turn (others; not you... I know you have been there, done that and have the t-shirt) that I hesitate to respond/ask...

You, Ian and others, have commented on the insurance woes for multihulls down under.  Here in the US we have no issue for the same boats.  Do you have any idea why the issue exists in your neck of the woods?  Greater frequency of capsizes?  Fewer insurers?  Many more one off or custom builds?  Inexperienced owners?  Worse weather leading to more capsizes (but then I would expect we would have an issue here and San Fran would stick out but not so...)?  Not disagreeing with you but genuinely curious why the insurance issue is such a problem for your area and not others.

Wess

PS - It sure would be nice if all the folks posting here about coulda, woulda, shoulda, would at least post a disclaimer about if they have ever owned and the offshore distance they have sailed on a large performance cruising multihull (trimaran or catamaran) that they owned - in others words crewing, skippering or owning a Hobie don't count - so folks could differentiate informed opinion from speculation.

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I have sailed over 22,000 miles aboard Cat2Fold, a freestanding, rotating, biplane rigged Catamaran. Each of my masts weigh just over 100lbs! I can carry them around the work yard by myself! Is my boat better at absolutely everything you want in a boat? Absolutely not. No boat has that! But, do I LOVE the way my boat cruises dead downwind better than ANY other boat I’ve ever come across, or how I can safely dump the sheets on any point of sail, or how wide open my decks are to enjoy with no foresails needed (unless you want more strings to play with in lighter air)  or how safe and easy it is to handle two, low aspect , low COE sails, using only a 4:1 tackle like an oversized sailing dinghy???? ABSOLUTELY!!!

I’ve sailed on enough other cats to know that my boat doesn’t necessarily excel at the same points of sail as traditionally rigged cats, but I know that my boat does excel on points of sail that others do not. Add to that the calm, comfortable feeling I have while hauling ass, knowing I can depower in an instant without even touching them helm, the ease of tacking upwind by only pushing/pulling the tiller, and I’m really blown away there are not more boats out there, multi and mono, that don’t use freestanding masts. In my simple mechanical mind, unprejudiced by decades of sailing “experience”, using rotating, freestanding rigs is a NO BRAINER! 

Coincidentally, Cat2Fold, the only 36’ folding, trailerable Catamaran is listed for sale (Yes, I bought an add), in order to hopefully get enough money together to purchase a much large multihull... A 20m HarryProa!!! Got my fingers crossed, and my eyes fixed on the stars! TO INFINITY...AND BEYOND!

 

7CE296D8-4945-4E45-A200-76C6C8B6B3A2.jpeg

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45 minutes ago, Bruce Sutherland said:

Wess - honesty behind the bull and the no names  .... you will be expecting manners next or maybe its all just fake news anyway?

Rgds Bruce 

 

Yea, LOL I should have used the sarcasm font and emoji for my PS comment.  Kinda funny how many words have been written by folks that AFAIK have never owned or even sailed as crew any appreciable offshore nm on a performance cruising cat or tri.  Never mind inshore.  Never mind ever.  But yea, its SA so lots of spit-balling.  Comes with the territory.

Did your's come across for this?  Hope all is well if so and if not I hope spring springs shortly!  Y'all may have had more snow than we did this year.

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Disclaimer.  I'm a lifelong mono--hull sailor(current boat owned for over 30 yrs) of many sizes who has chartered a couple of 47 foot cats and fucked around on a Hobie 18 here and there. In younger days, I was lucky enough to mess around on an unstayed, canting mast sailing craft originally called a Windsurfer.  I've enjoyed following Fujins build process in another thread, and have enjoyed some but not all of the posts here.

Still interested in the original topic but as a bonus, I'll happily wait for  posted numbers on a tacking dual between a Proa  and a Catamaran.

Please don't inform any thread nannies out there about my ill-informed comment on there being no assistant traveller trimmer in the posted video, or that I might be reading some of DDW's and other's insightful comments and trying to learn a thing or two.

 

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Stayed or unstayed: sailing's 2nd Amendment battle rages strong.  Who will be on the right side of history?  Stay tuned (NPI)

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17 hours ago, Monkey said:

Christian, just use the same filter I do. Take every claim he makes that uses the words could, should, or would, and throw them in the garbage can. Everything else he says is usually good reading. 

There may be some good stuff buried in the bullshit - I just have a tendency to write of posters when they present some utter BS whoppers.

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On 3/14/2018 at 3:20 AM, harryproa said:

Airwick.

We intended to use a canting (and raking) rig on the Volvo Proa, particularly for lake sailing where a maximum length boom would have provided too much weather helm.  volvoproa.pdf

I leave it to the pedants to decide whether this rig is stayed or not.  

Testing the canting is one of the things on the to do list for the foiling harry below.  

That is not very polite.  It may not be a "fact" for your boat where you have to lower and raise rudders and jibs, and rely on leeway and subsequent drag from the daggerboard to rotate the boat, but I can assure you it works well on a boat where there is nothing to raise and lower and the rudders work as foils to rotate the boat.  

Happy to record some tracks/make a movie when i get some time.  However,  my boat is in pieces while I investigate foiling

and this has been put on hold while I do some materials testing for the 24m sailing cargo/ferry which we will be building for Pacific islands use next year. http://harryproa.com/?cat=51    

Christian,

No, I am not on drugs.  I have spent 20+ years developing proas, experimenting with every configuration I (and many other interested people) could come up with.  The results are what I posted.       

I presume you could not come up with a scenario to support your contention that  "proas would be a clusterfuck racing with conventional boats"?   

HP Cargo Ferry 009.jpg

If you cannot see this yourself you are beyond help

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2 hours ago, r.finn said:

sailing's 2nd Amendment battle rages strong

Shouldn't that be the right to bear-away?

 

1 hour ago, Christian said:

If you cannot see this yourself you are beyond help

Agreed, it should be pretty evident to anyone who has been at a busy mark rounding and knows what a shunt looks like that it would generate some "interesting" (and not in a good way!) situations! And probably require a rewrite of the rules to...

Don't get me wrong, I like the "out of the box" thinking or proas and I think they have a lot more potential/appeal for cruisers than racers, just like unstayed masts on cats!

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    Not sure how many posting here have actually been on a race course in a multihull and found themselves about to roll a close hauled proa when its skipper realizes that they need to do a shunt or get hosed. I have while at the helm of a Newick 40 tri and it was non other than Russell on his proa during the Tashmoo Dash. Russell had plenty of time to make his shunt but I was not mentally prepared for what I was about to witness! It was impressive how quickly the proa stopped in its tracks and there was a brief but well practiced flurry of activity on board and I was wondering whether to call starboard or bear away but then the proa just squirted across my bows and was back up to speed with plenty of room to spare. Winds were light and the water was smooth but the current at the time could have made the situation even more dicey with the current that was running or it had happened at a mark with other boats in the immediate area. That was nearly 32 years ago and it still impresses me. The race was a reverse handicap and that crossing probably would have never taken place if it were not for the staggered start. Fun day especially to get to spend the after race party right in  Dick Newick the Mans backyard! Thanks for making it interesting Russ.

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21 hours ago, plywoodboy said:

If only the facts could be shared on this. A very sad clusterfuck. Suffice to say shared ownership, newbies, no pfd's, weather (30 knots plus squalls) so foul I had to sit on my sailboard (in protected waters with a 4.5 sqm sail) to stop it disappearing down the beach, and one of the clear pics of this boat showing a submerged sail deployed from the bowsprit, dinghy on the nets.....

A lot of angry guys down here looking at our muppet-indexed insurance premiums going up.

Yes the conditions were atrocious.  I am at a loss to explain the fascination with Jackets however, no one is in the water and they are barely getting their feet wet.  What was a big failure here was the lack of accessibility to EPIRB or PLBs.  Had they been utilised I doubt the matter would have made the news, it would have been all over quickly.  BTW - here is the boat a couple of days ago happily parked at WMYC.  I am sure there is some work to do, but she is upright and remarkably good nick.

29186673_1572938242813650_3195447988822474752_o.jpg

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20 minutes ago, ozmultis said:

Yes the conditions were atrocious.  I am at a loss to explain the fascination with Jackets however, no one is in the water and they are barely getting their feet wet.  What was a big failure here was the lack of accessibility to EPIRB or PLBs.  Had they been utilised I doubt the matter would have made the news, it would have been all over quickly.  BTW - here is the boat a couple of days ago happily parked at WMYC.  I am sure there is some work to do, but she is upright and remarkably good nick.

29186673_1572938242813650_3195447988822474752_o.jpg

Wow, that looks really good for a boat that was recently inverted in bad weather.

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