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Chris White carbon 70ft cat w/ freestanding rig

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carbon 70ft cat with a Freestanding Rig is on his site a while now, no details yet...

very fresh idea in the all turbo gunboat HH marketplace

Ultra fast and bold rig, anybody got an idea what the plan is for this beast?

schionnings style sidebyside or juniper style?

 

 

From Chris website

he all new Atlantic 70F (free-standing rig) is an ultra fast and easy to handle 'couples' cruiser. Her owners are very experienced sailors; they circumnavigated in the early 1980s, recently owned an Atlantic 55, and are competitive racers at their yacht club. The A70F is long, lean and light, built in all pre-preg carbon fiber. With the owners' tremendous sailing experience comes specific requirements, bold ideas for the rig and other aspects of the project, and extensive involvement with the design and construction.

This design is a collaboration of many, including Chris White Designs, the owner, the builder Goetz Composites, SDK Structures, Doyle Sails, Southern Spars, and Persak and Wurmfeld.

Launch is scheduled for early 2017.

carbon 70ft cat with a Freestanding Rig!!?!?

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Is this the one with the biplane rig?

 

I talked to Chris about designing a smaller biplane freestanding rigged cat a while back. He wasn't sure it was a good idea then.

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I have no idea, but the text excludes his mast foil and planting freestanding masts at centerline is horror in cats so i guess its team phillips style right?

but then saying it will be ultra fast.. so hyping it or really innovating, that would be interesting.

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Yes. For a repeat experienced customer. One nice feature is you never get caught if the breeze comes up out in the ocean. You can just let the sails all the way out and put in a reef at leisure.

 

I think they took a 30' or so cat and did a prototype.

 

 

Is this the one with the biplane rig?

 

I talked to Chris about designing a smaller biplane freestanding rigged cat a while back. He wasn't sure it was a good idea then.

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Yes. For a repeat experienced customer. One nice feature is you never get caught if the breeze comes up out in the ocean. You can just let the sails all the way out and put in a reef at leisure.

 

I think they took a 30' or so cat and did a prototype.

 

 

Is this the one with the biplane rig?

 

I talked to Chris about designing a smaller biplane freestanding rigged cat a while back. He wasn't sure it was a good idea then.

 

Freestanding masts have there good points. DDW is one of them...

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Yes. For a repeat experienced customer. One nice feature is you never get caught if the breeze comes up out in the ocean. You can just let the sails all the way out and put in a reef at leisure.

 

I think they took a 30' or so cat and did a prototype.

 

 

 

Is this the one with the biplane rig?

 

I talked to Chris about designing a smaller biplane freestanding rigged cat a while back. He wasn't sure it was a good idea then.

 

Freestanding masts have there good points. DDW is one of them...

Exactly! Also...Chris White spent a few hours hanging out aboard quizzing me, and checking out Cat2Fold's rig a couple years ago, with this 70' project in mind. Super cool and smart guy to hang with!

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Freestanding masts have there good points. DDW is one of them...

 

 

 

 

 

 

 

Yes I am one of them :). On mine, I can reef running DDW.

 

Will it be wishbones or booms? Rotating masts or fixed? Enquiring minds want to know.....

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Will it be wishbones or booms? Rotating masts or fixed? Enquiring minds want to know.....

 

 

After Mr White slagged off mainsails when he came up with his crappy mast foil failure, who knows.

 

From https://www.chriswhitedesigns.com/mastfoil-discussion

 

CW writes.....

 

"For all the trouble associated with the mainsail, what do you get? Per unit of sail area, the mainsail is the least efficient sail on the boat. Sailing upwind, the mast - at the aerodynamically critical leading edge of the mainsail - robs a great deal of its power. ............. Also the large roach area of the sail contributes to significant weather helm which slows the boat and can make steering more difficult."

 

 

Whatever he does now he's going to look like a goose after that bowel movement.

 

He does have a good eye for a pretty boat, even if they do seem to fall over a little too regularly.

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One of those cats sits in my YC. I love to look at it on the way out and back in. I don't know the owner yet, but other club sailors say that he is happy with performance

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"For all the trouble associated with the mainsail, what do you get? Per unit of sail area, the mainsail is the least efficient sail on the boat. Sailing upwind, the mast - at the aerodynamically critical leading edge of the mainsail - robs a great deal of its power. ............. Also the large roach area of the sail contributes to significant weather helm which slows the boat and can make steering more difficult."

 

 

 

Well that is just ignorant, or perhaps marketing blather.

 

The world's fastest boats are una rigged, this is especially true in development classes with sail area as the only rule. Jibs were obsolete in those classes in the late 60s, well before wings became popular.

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Chris is on quite a streak. Billzo at Aquidneck Custom has a 70'(?) CW under contraction. Goetz has a 70. Not bad.

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CW writes.....

 

"For all the trouble associated with the mainsail, what do you get? Per unit of sail area, the mainsail is the least efficient sail on the boat. Sailing upwind, the mast - at the aerodynamically critical leading edge of the mainsail - robs a great deal of its power. ............. Also the large roach area of the sail contributes to significant weather helm which slows the boat and can make steering more difficult."

 

 

Whatever he does now he's going to look like a goose after that bowel movement.

 

He does have a good eye for a pretty boat, even if they do seem to fall over a little too regularly.

 

 

 

It's always great to see the forum/armchair designers put in their 2¢. Please regale us with tales of your design accomplishments.

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It Will be interesting to see how CW is going to deal with the occasional accidental gybe and  the resulting boom tip classes.

 

image.png.0055f67a97fb89f1839a7e7624459744.png

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On 4/5/2017 at 7:00 AM, Mizzmo said:

One of those cats sits in my YC. I love to look at it on the way out and back in. I don't know the owner yet, but other club sailors say that he is happy with performance

I was kayaking by the mast foil  boat a couple years ago and met the owner in Hampton, he sailed it up from its build location in Chile and talked it up in terms of its heavy weather mast-only performance. I’m thinking, like the mast foil, there is more initial and maintenance cost but ease of operation will be attractive to a lot  of folks looking to get into the multihull game. 80+ foot masts are a PIA, two smaller ones have their place.

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Very nice, clean look.  I suspect it will sail quite well.  Wish I could....  (nah, too big, nah, it's probably a dog...)

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I'm not so keen on the lack of a forward cross beam (even if set 6' back from the bow) to handle the wracking loads. Sure you can build the middle strong enough but I bet it's not as structurally efficient.

So you've got these nets with a big hole that don't look very cruiser friendly, and no handrails on the cabin tops. Kinda odd.

Overall it looks very nice and slippery

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9 minutes ago, Zonker said:

So you've got these nets with a big hole that don't look very cruiser friendly,

Chris is very bright, so I suspect I'm just missing it, but I'd want an anchor bridle from the bows. I don't see cleats or fairleads for that.  Just for going walk about on the bows the setup looks okay to me. I'm sure that CW got the engineering right but it is a look that makes me wonder a bit about the "Team Phillips" wracking thing.

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2 hours ago, Zonker said:

I'm not so keen on the lack of a forward cross beam (even if set 6' back from the bow) to handle the wracking loads. Sure you can build the middle strong enough but I bet it's not as structurally efficient.

So you've got these nets with a big hole that don't look very cruiser friendly, and no handrails on the cabin tops. Kinda odd.

Overall it looks very nice and slippery

I'll leave the engineering to you, but, for mine, a simple beam & nets to bow thanks. After all, it's free real estate ;) 

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19 hours ago, overlay said:

It Will be interesting to see how CW is going to deal with the occasional accidental gybe and  the resulting boom tip classes.

 

image.png.0055f67a97fb89f1839a7e7624459744.png

It looks like there are 2 black lines coming from the bow back to near the anchor, that looks like it would make a good anchoring bridle setup (dont' see what else it could be as there is nothing sail related up front...

I dont' see why you would need a front beam since there is no forestay and related loads, and the main beam isn't that far back. I suppose a bigger net might be nice but only if you are going to have a bunch people on there, it looks like there's "enough" lounging room as-is. If anything, it might have been nice to not have the nets go all the way to the bow to reduce drag/spray when it goes through waves... It's not designed as a "wave piercer" but given the length and speed potential to freeboard it looks like it will go through some waves occasionally.

Looks like a nice easy to sail ride for sure!

 

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20 hours ago, overlay said:

It Will be interesting to see how CW is going to deal with the occasional accidental gybe and  the resulting boom tip classes.

 

image.png.0055f67a97fb89f1839a7e7624459744.png

I would’ve be quite surprised if CW didn’t design this boat to have the booms shorter than the distance between masts. And as far as accidentally gybing both sails into the center... it would take an idiot, actually trying to make that happen, for it to happen. Plus it sounds like the pivot of the masts are controlled electrically...

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Quote

I dont' see why you would need a front beam since there is no forestay and related loads, and the main beam isn't that far back

Because the hulls may experience different wave loads at different times (think beam seas or quartering waves) there are big structural loads on the hull connections.

The main beam does seem far back to me; at 30-35%, of LOA. Even if there was no forestay, I'd much prefer to have a beam at 10% aft of the bow.

The boat is all pre preg carbon so it's strong, but that doesn't mean it is efficient.

I'm not keen on the nets working that way because at the bow they taper to nothing; so you're standing on a skinny bow with a lifeline on only one side. On most cats it is very hard to fall overboard. On this one, it wouldn't be hard at 10' aft of the bow.

 

Structure: From Chris White's web site:

Quote

The design process involved many people, each of whom contributed their specific areas of expertise. SDK did the bulk of the structural engineering. 

The "DK" in SDK is Dirk Kramers who has a good reputation

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13 hours ago, Airwick said:

I dont' see why you would need a front beam since there is no forestay and related loads, and the main beam isn't that far back.

Because these images are hard to forget:

Team%20Phillips.jpg

 

That said, the build and engineering can be done right and I'd trust to CW make sure they got done right.

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The front fell off off that one. 

A cross beam resists wracking loads in torsion. For the beam then, it doesn't matter where on the boat it is, it's contribution is the same. There will be more bending load in the hulls feeding it to the beam, but usually the hulls are many times stronger than they need to be in bending. Team Philips excepted. 

The owner was apparently very involved in this project, so many of the decisions you see might be his, not CW's. I'm curious about how much extra speed they get from trimming the mast angle. I concluded it probably wasn't worthwhile, but here's a test bed.....

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I think of wracking as one hull tip going up as the other one goes down.  The beams resist this torsionally.  My prior cat was a 52’ alloy 3 beam cat that wracked a lot.  Beams flexed a lot in torsion.  

Philips looks like it failed from one hull tip going left while the other one went right.  In a monohull, big wave forces turn the boat.  In a big cat the hulls resist each other, creating much higher loads.  Even a small amount of different direction hull flex at the bows creates new and impressive loads.  The distance from the hull tips to the beam is a lever arm.  A cross beam at the tips sees much lower loads, than a beam further back.  Similarly the forward beam lowers the hull unsupported beam loads dramatically.  A no-forestay forebeam could be a lot lighter, without gull striker, etc.  I would guess the hull reinforcements required to eliminate the forebeam outweigh the forebeam.

But it is a pretty boat.

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12 hours ago, weightless said:

Because these images are hard to forget:

Sure... but that was a while ago.

If you look at modern ocean going multis, they have long skinny un-supported bows that are a lot more extreme that this 70ft cat and they don't seem to be breaking off the way they did on Phillips. This looks like it's only got about 20' unsupported, and each hull is wider than on those racing boats so you'd think it would be able to able to handle the loads fairly well. And some cats with traditional rigs are even dropping the front beam (GB 55) as well (although I have wondered about the overall efficiency of doing that as well).

The only thing I find a  bit odd is that it seems a bit inconsistent to forgo the front beam if you are not doing wave piercing/water shedding bows as well as not stopping the boat when going through waves seems like the biggest benefit of not having a front beam (the reduction of pitching inertia seems like a comparatively minor benefit). If I had to guess I would say they are keeping high freeboard at the bows to try and keep the boat drier for longer as I dont' see any other good reason for it...

Regarding wracking, the forward beams on most cruising cat are pinned at the end (their main function being to take the compression load from the forestay pulling the bows together) so that would do nothing to stop wracking. I'm guessing there would be a lot of stresses in that joint (because of the wracking) if it was made rigid and that's why they are pinned.

Regarding falling overboard, I agree a bigger net would be better but on the other hand there is essentially no need to be near the bows when under way on such a boat.

 

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+1^  Nice reply to the other criticisms Airwick. This is one very cool cat and congratulations to the owners and designer for launching this state of the art bi- plane multi. A good reason for not having nets going right to the bows in a lightweight cruising cat is the windage they can create if caught in extreme conditions. I’ve heard of a couple of cats going over backwards here in Oz caught in thunderstorms , and as Airwick says, you don’t need to go forward in this design. The only drawback I can see in this setup would be retrieving the anchor once the bridle was disconnected, with such a long distance from the bows to anchor roller she sure is going to be hard to keep the bows from sailing off when it’s blowing. Apart from this ‘Saphira’ is my idea of the ultimate cruising boat!

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6 hours ago, Airwick said:

the forward beams on most cruising cat are pinned at the end

On CW's Atlantic series (at least all of them that I've been on) the forward beam is rigidly attached.

Wave piercing bows would probably make the center cockpit wetter for no meaningful gain in performance in the context of a cruising cat. Also, you'd lose interior volume. It's a cruising cat. Someone important to the owner may sleep up there.

It is a lovely boat, I'm sure it'll be a joy to sail and I have no doubt that it'll be plenty tough enough for voyaging. Every design is a compromise. We can discuss the choices that have been made and admire the design.

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On the A42 at least, the front beam is an aluminum extrusion that is attached by four bolts through a small flange. While "rigid", it isn't going to resist much moment in any direction. It is intended to resist shear upwards, not much else. If the worry is one bow bending sideways in a wave, then this sort of front beam will carry some load through to the other hull, doubling the resistance. But on a cruising cat with that kind of hull section, if you are in a seaway that is endangering the bows, your hours are numbered in any case. 

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On 6/9/2018 at 4:45 PM, SCANAS said:

I'll leave the engineering to you, but, for mine, a simple beam & nets to bow thanks. After all, it's free real estate ;) 

For no other reason than real estate... completely agree.... makes no sense to me

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5 hours ago, DDW said:

On the A42 at least, the front beam is an aluminum extrusion that is attached by four bolts through a small flange.

On my Atlantic 42 there are 10 bolts per side on a substantial flange. YMMV.

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I did say most... If this design doesn't need a beam up front then it's one less piece of hardware so why not...

Net real area is obviously a personal choice although a couple living on 70' cat probably aren't trying to squeeze the last bit of real estate.

It seems to me that the biggest benefit of "wave piercing" bows on a cruiser like this would be to reduce the windage up front, which would make tacking easier in big conditions. Especially with a light boat that probably doesn't have a ton of rocker (and no jib to backwind). The tradeoff would be that it's harder to walk on and would make the front cockpit wetter.

Either way it's a cool design, are any pictures/plans of the interior layout?

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9 hours ago, weightless said:

On my Atlantic 42 there are 10 bolts per side on a substantial flange. YMMV.

Apparently it does vary, this is the one I was test sailing. But it doesn't matter, the base plate and laminate that it is bolted through are going to fail in bending with a hard tug. These were not designed to resist torsional twisting of the planform, and don't.

dLS7KRh.jpg

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Consider designs such as the Gunboat 55 which have a longeron for the headstay tensions and minimal cross beam support. (if any)  Or, take a look at the HH catamarans.  This discussion of a fwd cross beam being essential so the front doesn't fall off is mostly irrelevant.  YMMV.

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5 hours ago, DDW said:
15 hours ago, weightless said:

On my Atlantic 42 there are 10 bolts per side on a substantial flange. YMMV.

Apparently it does vary

Yep. There are custom, small production and home built A 42s out there. The early ones had a simpler setup with a headstay bridle. On mine and I think most of the later ones the headstay goes to the beam. In those cases the beam is typically more substantial and has a seagull striker and compression post. Also, turns out mine has 9 bolts per side, FWIW. The flange, extrusion and attachment look a good deal beefier than the one you show. So, what annoyed me about your post was the statement about "the" A42. You've seen one but you have not seen them all. They differ in many ways.

Here's the thing: I agree, there's no problem with the two beam setup. In theory, the rigging and the beam make the boat stiffer and stronger all else being equal. In practice it's not going to matter.

So, to the folks who think the nets should go bow to bow, how'd you setup the anchor system?

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Its a beautiful boat.  Damn.  I think if you guys look a bit harder you may conclude they are not wave piercing bows.  Quite traditional actually.  The lack of a forward beam reduces weight (where you least want it) and the net design make anchor handling much less difficult.  For something that's not a marina queen and double handed, that's a nice feature, no?  Anyway, to each his own but for me that is a cool boat and innovative design. I would be really curious to see how she weighs in compared to her "sistership" the conventional rigged 72. Very curious how much structure is needed for the freestanding rid and of course the weight of the second mast but damn what a nice toy and voyaging yacht.

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Adrian Thompson is a clever guy, forgot how radical that boat was. It's hard to do good work in those long narrow hulls, essentially you build the halves, glue them up and hope you never have to go there. I seem to remember there was extensive forensic on that and the problem given most weight in the failure was not debulking/cooking the many layers enough. 1999 was a whi.e ago in composite terms. CW's hulls are mpre capacious, the laminates less comp,ex, I suspect.

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Team Phillips was building their boat themselves with a long term goal to become a composites company beyond the life of The Race.  

I would have loved to have seen how that boat performed around the world against the more conventional cats.  The hulls remind me of a more radical, scaled up Gougean 32 that was dedicated to wave piercing.

 

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