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Lifting Keel For Donovan GP26: Level of interest? Ideas on Design?

Lifting keel sportboat Sportboat GP26 Donovan26 Wraceboats

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#1 windseekeryachts

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Posted 09 September 2012 - 06:55 PM

We received some enquiries for a lifting keel version for the 26 footer and already had some discussions with Jim about the design. This forum is for seeing the level of interest and gathering some information about design from potential target audiance

#2 Icebear

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Posted 09 September 2012 - 07:06 PM

Lift keel would put this on the top of my list for a

mid-20s sport boat with cuddy. A fast and versatile boat for US lakes and nearshore.

Also interested in the Donovan 6 with retractable keel.

#3 Jim Donovan

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Posted 09 September 2012 - 07:29 PM

Current plans are to lift the keel approx 4 feet, reducing draft about 2 feet.
If trailer launching is required, then an arrangemet that lifts higher would be required.

#4 rantifarian

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Posted 09 September 2012 - 11:02 PM

Is the boat going to be sailable withe the keel lifted, and are there going to be any changes to the rudder setup?

#5 Jim Donovan

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Posted 10 September 2012 - 01:34 AM

Is the boat going to be sailable withe the keel lifted, and are there going to be any changes to the rudder setup?


The boat will need the keel lowered to full depth and locked in place for sailing.
There are several possibilities for rudder arrangements.
Currently we are looking at twin rudders in cassettes.

#6 Ryley

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Posted 10 September 2012 - 01:35 PM

How do you think twin rudders will affect performance? Would the rules allow for a transom-hung rudder, or would that be outside the GP26 box?

I'd only be interested if the lifting keel gave ramp launch performance. While I keep my current boat in the water most of the time, I don't have access to a hoist so for away regattas, ramps are my only option. Or an inboard diesel and an autopilot ;) Otherwise, I don't really see the point to a lifting keel.

#7 Jim Donovan

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Posted 10 September 2012 - 02:36 PM

How do you think twin rudders will affect performance? Would the rules allow for a transom-hung rudder, or would that be outside the GP26 box?

I'd only be interested if the lifting keel gave ramp launch performance. While I keep my current boat in the water most of the time, I don't have access to a hoist so for away regattas, ramps are my only option. Or an inboard diesel and an autopilot ;) Otherwise, I don't really see the point to a lifting keel.


My intention is exactly that; to have a lifting keel option that allows ramp launching.


The twin rudder solution is the best for an outboard mounted rudder - a single outboard mounted rudder would not be as good as the single inboard mounted rudder.Although the class doesn't allow twin rudders now, I would hope they would consider this option.

There are quite a few potential owner's that might move into the class if a good shallow water/ramp launch arrangement is allowed.

#8 SA Lurker

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Posted 10 September 2012 - 03:16 PM

[There are quite a few potential owner's that might move into the class if a good shallow water/ramp launch arrangement is allowed.


+1 (more)

#9 Steam Flyer

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Posted 10 September 2012 - 05:04 PM


How do you think twin rudders will affect performance? Would the rules allow for a transom-hung rudder, or would that be outside the GP26 box?

I'd only be interested if the lifting keel gave ramp launch performance. While I keep my current boat in the water most of the time, I don't have access to a hoist so for away regattas, ramps are my only option. Or an inboard diesel and an autopilot ;) Otherwise, I don't really see the point to a lifting keel.


My intention is exactly that; to have a lifting keel option that allows ramp launching.


The twin rudder solution is the best for an outboard mounted rudder - a single outboard mounted rudder would not be as good as the single inboard mounted rudder.Although the class doesn't allow twin rudders now, I would hope they would consider this option.

There are quite a few potential owner's that might move into the class if a good shallow water/ramp launch arrangement is allowed.


Yes!
Count me among that number.

Twin rudders in cassettes might be easier to implement than a turret/trunk arrangement for an inboard rudder. But if the inboard rudder has significant performance advantage, that might be the most sensible way.

A boat that is offshore capable, kicks a Mumm 30's ass, and is trailerable?? FFS who -wouldn't- want one???!?!!

FB- Doug

#10 GybeSet®

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Posted 10 September 2012 - 08:15 PM

does not beat Mumms

#11 Heriberto

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Posted 10 September 2012 - 08:50 PM

does not beat Mumms


Oh really. You speak with authority on this because you've seen a Donovan GP26 race against a Mumm? Where? That would be a neat trick, because there is only one boat in Hong Kong that is brand new and still shaking out the lumps, and the boat in Turkey, which is also still in the earliest phases of learning its potential.

Jim hasn't said it would beat a Farr 30, and I don't know if it would, but I do know you don't know either way. Now, if Jim said he was confident this boat would beat a F30 in most conditions, or a set of conditions, I think he would be speaking from a strong position of authority on the subject.

#12 Icebear

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Posted 11 September 2012 - 02:02 AM



How do you think twin rudders will affect performance? Would the rules allow for a transom-hung rudder, or would that be outside the GP26 box?

I'd only be interested if the lifting keel gave ramp launch performance. While I keep my current boat in the water most of the time, I don't have access to a hoist so for away regattas, ramps are my only option. Or an inboard diesel and an autopilot ;) Otherwise, I don't really see the point to a lifting keel.


My intention is exactly that; to have a lifting keel option that allows ramp launching.


The twin rudder solution is the best for an outboard mounted rudder - a single outboard mounted rudder would not be as good as the single inboard mounted rudder.Although the class doesn't allow twin rudders now, I would hope they would consider this option.

There are quite a few potential owner's that might move into the class if a good shallow water/ramp launch arrangement is allowed.


Yes!
Count me among that number.

Twin rudders in cassettes might be easier to implement than a turret/trunk arrangement for an inboard rudder. But if the inboard rudder has significant performance advantage, that might be the most sensible way.

A boat that is offshore capable, kicks a Mumm 30's ass, and is trailerable?? FFS who -wouldn't- want one???!?!!

FB- Doug


Count me as well as one who prefers a ramp launchable setup.

#13 Jim Donovan

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Posted 11 September 2012 - 02:45 AM

Sounds like ramp launching is the strong preference.
Twin outboard rudders will potentially have very similar performance to the single inboard rudder.

Re: comparison to a Farr 30 (ex- Mumm 30)
I've never even considered this comparison; the Farr has a very powerful rig and is nearly 6 feet longer, so one would expect it to be generally faster.
I would expect in some conditions the GP 26 will be faster; marginal planning conditions and heavy air running when the Farr has some control "issues".

The report from the windy race last weekend (20+ knots TWS) is that the GP 26 had sustained periods at 15 knots, some at 17 knots.
This is quite quick for a fixed keel 26 footer, especially one with such a heavy keel.

Along with this excellent downwind performance comes as really good upwind speed; they report 6.5 knots is typical upwind speed.

#14 GybeSet®

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Posted 11 September 2012 - 08:53 AM


does not beat Mumms


Oh really. You speak with authority on this because you've seen a Donovan GP26 race against a Mumm? Where? That would be a neat trick, because there is only one boat in Hong Kong that is brand new and still shaking out the lumps, and the boat in Turkey, which is also still in the earliest phases of learning its potential.

Jim hasn't said it would beat a Farr 30, and I don't know if it would, but I do know you don't know either way. Now, if Jim said he was confident this boat would beat a F30 in most conditions, or a set of conditions, I think he would be speaking from a strong position of authority on the subject.


you are dreaming mate, with your hypotheticals

I do know 1st hand what a 'GP26' cannot do, & read up on the designers comment

#15 Dale dug a hole

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Posted 11 September 2012 - 10:44 AM



does not beat Mumms


Oh really. You speak with authority on this because you've seen a Donovan GP26 race against a Mumm? Where? That would be a neat trick, because there is only one boat in Hong Kong that is brand new and still shaking out the lumps, and the boat in Turkey, which is also still in the earliest phases of learning its potential.

Jim hasn't said it would beat a Farr 30, and I don't know if it would, but I do know you don't know either way. Now, if Jim said he was confident this boat would beat a F30 in most conditions, or a set of conditions, I think he would be speaking from a strong position of authority on the subject.


you are dreaming mate, with your hypotheticals

I do know 1st hand what a 'GP26' cannot do, & read up on the designers comment


Dont worry Heriberto, his Mummy has put him to bed. And his computer privileges have been cut because he didn't do the dishes

#16 set321go

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Posted 11 September 2012 - 11:31 AM


does not beat Mumms


Oh really. You speak with authority on this because you've seen a Donovan GP26 race against a Mumm? Where? That would be a neat trick, because there is only one boat in Hong Kong that is brand new and still shaking out the lumps, and the boat in Turkey, which is also still in the earliest phases of learning its potential.

Jim hasn't said it would beat a Farr 30, and I don't know if it would, but I do know you don't know either way. Now, if Jim said he was confident this boat would beat a F30 in most conditions, or a set of conditions, I think he would be speaking from a strong position of authority on the subject.


If you go to Manage/Ignore preferences you can turn the troll off, now if you would refrain from quoting GSBS I would never have to hear of him again

#17 Heriberto

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Posted 11 September 2012 - 11:45 AM

Dont worry Heriberto, his Mummy has put him to bed. And his computer privileges have been cut because he didn't do the dishes


I wonder if he knows what an IMS boat "can do", or what a mini "can do". Like most reasonable people, and given the reports and the videos and the race results, I would have guessed (and Jim would be the one to know, and says so) the Mumm will likely be faster in most light/medium air conditions, but in some condiitons, like marginal planing or heavy air reaching, and maybe some more conditions, a GP26 will dust it. To the point of kicking it's ass.

And again, there are GP26's and there are (and will be) GP26's. Some are going to be faster than others, some maybe a lot faster in some conditions.

But then, there are some people who are not "most" people. They are special. There is a place for them here on SA.

As for the twin rudder design, it's hypothetical at this point, but I think if I had an existing boat, I would want to make sure there wasn't a performance advantage to going with this setup. It does get a little problematic, since a lifting keel boat would have more weight in structure and systems related to that purpose, so you would likely see a performance hit on that end. So you would be wondering, ok, would a fixed keel, twin rudder boat perform better under X conditions than a fixed keel single rudder? You would have to tailor the rule so it doesn't favor one build over another, which makes it more complicated. Some people are going to not need a lifting keel and not want the added expense or performance hit. But the people who do want it aren't going to want to have to pay extra, and still carry a performance hit.

A delicate balance.

#18 Heriberto

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Posted 11 September 2012 - 11:46 AM

If you go to Manage/Ignore preferences you can turn the troll off, now if you would refrain from quoting GSBS I would never have to hear of him again


Done. Sorry. It wasn't as bad a Vwap or DoRag, but yeah.

#19 Ryley

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Posted 11 September 2012 - 01:41 PM

Heriberto, I'd be more concerned if we were taking a class like an M24 and modifying it, but I think that within the box rule, it should be relatively straightforward. Not to mention that at least in this class there are enough modeling tools available that from a strictly empirical standpoint it should be fairly easy to codify the differences.

As far as cassettes go, I understand their ease as far as putting them on, especially at a ramp; however, my experience with cassettes is that they add a level of complexity and breaking points you don't necessarily want. They also add weight, even in the best conditions. Both the US Elliotts and the FT10s, with radically different approaches to cassettes, have had problems with them. I'd rather see two single-pin rudders. at most ramps that I go to, if they're 3' or less, you could get to the channel with the keel up and the rudders in. Otherwise, steer with the outboard until you get to the dock or mooring.

As far as the lifting keel, Jim, I took your first set of comments to mean that you weren't looking at ramp launching. Thank you for the clarification. On my Elliott (which has its own sets of drawbacks), the keel is lifted by an 8:1 block and crane permanently mounted to the deckhouse, and the lifting line goes to a 2-speed winch on the cabin top. This works fine for an 850lb keel, not sure how something like that would work with the GP26's considerable ballast, but the advantages it provides is that 1: you can go off a shallow ramp and get to the channel before dropping the keel, 2: you don't have another piece of equipment that you have to rig (and store) to raise and lower the keel - it's all part of the normal sailing inventory. I'm not sure how they do it on the Antrim 27s but I do like that there isn't a keel trunk taking up the whole interior of the boat like there is on the Elliott.

#20 PurpleOnion

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Posted 12 September 2012 - 01:07 AM

We received some enquiries for a lifting keel version for the 26 footer and already had some discussions with Jim about the design. This forum is for seeing the level of interest and gathering some information about design from potential target audiance


I would definitely be interested in such a beast. Assuming that pricing didn't go through the roof, this would be a tremendous value and check pretty much every box on my list.

#21 mentalasanything

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Posted 12 September 2012 - 05:01 AM



How do you think twin rudders will affect performance? Would the rules allow for a transom-hung rudder, or would that be outside the GP26 box?

I'd only be interested if the lifting keel gave ramp launch performance. While I keep my current boat in the water most of the time, I don't have access to a hoist so for away regattas, ramps are my only option. Or an inboard diesel and an autopilot ;) Otherwise, I don't really see the point to a lifting keel.


My intention is exactly that; to have a lifting keel option that allows ramp launching.


The twin rudder solution is the best for an outboard mounted rudder - a single outboard mounted rudder would not be as good as the single inboard mounted rudder.Although the class doesn't allow twin rudders now, I would hope they would consider this option.

There are quite a few potential owner's that might move into the class if a good shallow water/ramp launch arrangement is allowed.


Yes!
Count me among that number.

Twin rudders in cassettes might be easier to implement than a turret/trunk arrangement for an inboard rudder. But if the inboard rudder has significant performance advantage, that might be the most sensible way.

A boat that is offshore capable, kicks a Mumm 30's ass, and is trailerable?? FFS who -wouldn't- want one???!?!!

FB- Doug


The Sydney GP26 seems to be plenty slower than Mumm's. Too much bulb and too little rig?

Not that theres anything wrong with that. It is what it is.

#22 Heriberto

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Posted 12 September 2012 - 01:04 PM

A Farr 30 has about 25% more waterline than a GP26. An early TP52, has 30% more waterline than a Carkeek 40 or similar class HPR40. In non-planing conditions waterline rules. Why is that concept hard to grasp in a sportboat forum? Fighting that battle every year with ratings committees. ORC also has a GP33 class. Would like to see a Mumm kick those. Don't get me wrong, the Mumm is/was a great boat, so were the early TP52's, but they won't plane or surf like a modern boat such as a Carkeek 40 or Donovan GP26.

#23 set321go

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Posted 12 September 2012 - 01:19 PM

A Farr 30 has about 25% more waterline than a GP26. An early TP52, has 30% more waterline than a Carkeek 40 or similar class HPR40. In non-planing conditions waterline rules. Why is that concept hard to grasp in a sportboat forum? Fighting that battle every year with ratings committees. ORC also has a GP33 class. Would like to see a Mumm kick those. Don't get me wrong, the Mumm is/was a great boat, so were the early TP52's, but they won't plane or surf like a modern boat such as a Carkeek 40 or Donovan GP26.


why does it matter? Because really were gonna buy the biggest fastest boat we can. If I could affort a farr30 I wouldnt consider buying a gp26, but should i be lucky enough to affort a tp52 i would probably have enough cash to have more than one boat!

#24 set321go

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Posted 12 September 2012 - 01:24 PM

How long would twin rudders need to be? Could you have fixed twin rudders instead of cassettes? you then get the benefit of an inboard rudder and reduced draft

#25 Heriberto

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Posted 12 September 2012 - 01:46 PM

The Melges 32 finally came up with a workable solution that kept the class from imploding. I think a similar concept would work well. The concept I have in mind is a watertight shaft that goes through the whole boat, sized large enough to slide the rudder through. The bearing assembly, bearing housing and rudder are kept as complete one unit which fits in that shaft, creating a flush surface at the bottom of the hull.

This would be simpler, much cheaper, and much lighter than twin transom hungs and wouldn't introduce the "unknown factor" that twins would add. Depending on design, it would also be much more robust. Only problem is you wouldn't be able to use a belowdecks autohelm for anybody that wanted to shorthand.

There are always tradeoffs.

#26 Christian

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Posted 12 September 2012 - 03:43 PM

The Melges 32 finally came up with a workable solution that kept the class from imploding. I think a similar concept would work well. The concept I have in mind is a watertight shaft that goes through the whole boat, sized large enough to slide the rudder through. The bearing assembly, bearing housing and rudder are kept as complete one unit which fits in that shaft, creating a flush surface at the bottom of the hull.

This would be simpler, much cheaper, and much lighter than twin transom hungs and wouldn't introduce the "unknown factor" that twins would add. Depending on design, it would also be much more robust. Only problem is you wouldn't be able to use a belowdecks autohelm for anybody that wanted to shorthand.

There are always tradeoffs.

That solution is a more than 15 year old solution called Vara and cooked up at Soca for the Henderson 30. It definitely is not a cheaper solution than dual rudders

#27 Heriberto

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Posted 12 September 2012 - 04:00 PM

No it is not the VARA design. I'm talking about a conventional rudder and conventional rudder stock with conventional bearings like the self-aligning JEFA bearings but the bearing assembly is in a cassette that fits in a shaft from the cockpit floor to hull exterior. The bottom of the bearing cassette would need to be fair with the hull bottom.

Two faired foils, two tillers, two rudder mounts, a linkage assembly vs. one extra rudder shaft housing and some fairing. Which is cheaper and lighter?

#28 Steam Flyer

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Posted 12 September 2012 - 05:30 PM


...

A boat that is offshore capable, kicks a Mumm 30's ass, and is trailerable?? FFS who -wouldn't- want one???!?!!

FB- Doug


The Sydney GP26 seems to be plenty slower than Mumm's. Too much bulb and too little rig?

Not that theres anything wrong with that. It is what it is.


Yeah, sorry guys. I was goofing with the "kicks a Mumm 30's ass" remark. They are very different boats, and with those differences come some strengths & weaknesses... Jim says there are some conditions / points of sail where the GP26 would outrun one, but most of the time it wouldn't... first of all, he should know and second of all, he's being honest.

Rudder- I've seen a couple of different implementations of the VARA rudder idea... basically it's a trunk in a rotating drum, sometimes called a turret... and yeah it would not be the cheapest way to implement a lifting rudder. The fairing of the bottom of the turret to the hull can't really be done without compromising hull shape, AFAIK.

Lifting keel & trunk... couple ideas on that one. The biggest compromise here is the foil length versus the amount of hoist. Then there's the issue of parallel foilsection so it doesn't slam around in the trunk when hoisted.

I think if you could make as much as 60% of the foil parallel, it wouldn't be too big a performance hit and bring the top of the foil somewhat above the trunk, that looks like it gives you close to 1.7m of hoist... not quite enough to get the bulb snugged up to the bottom of the hull for low trailering & ramp launching, BUT it would give shallow water operating capabilty. To get it up those last 1/2m how about a temp crane like the Melges use for their keel but it would only be needed to bring the keel up all the way snug for ramp launch/recovery. Yes that leaves a trunk blocking up the cabin BUT it also gives a nice girder strengthening the hull and making it a lot stiffer.

FB- Doug

#29 Christian

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Posted 12 September 2012 - 10:36 PM

No it is not the VARA design. I'm talking about a conventional rudder and conventional rudder stock with conventional bearings like the self-aligning JEFA bearings but the bearing assembly is in a cassette that fits in a shaft from the cockpit floor to hull exterior. The bottom of the bearing cassette would need to be fair with the hull bottom.

Two faired foils, two tillers, two rudder mounts, a linkage assembly vs. one extra rudder shaft housing and some fairing. Which is cheaper and lighter?


When did Melges change the rudder set-up? Sounds like an expensive switch-out knowing typical Melges pricing.

#30 Jim Donovan

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Posted 13 September 2012 - 07:32 AM

The VARA system rudder solves several issues: it allows for an inboard rudder location, and allows the rudder blade to be lifted and still steer the boat.
It is a relatively complicated system, not inexpensive, and I've heard a few complaints regarding bearings and movement in the system.

A single cassette rudder can be built as light as an inboard rudder, and it would take some on-the-water testing to determnine if it is as good a solution for performance as the inboard rudder.
The difference could be quite small.

Twin outboard rudders are quite good for windy reaching and running, and you might get away without cassettes as the rudders have about half the draft as the inboard rudder.

The information I have shows that the Antrim 27 keel does not lift completely; only 2.7 feet.
Is it possible to ramp launch an Antrim 27 with nearly 2.5 feet of keel sticking out from the hull bottom?

#31 Forza

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Posted 13 September 2012 - 11:22 AM

Use one rudder in a cassette, reduce the draft to match an Esse 850 (or better ) . The design is better than an Esse 850, even with the constraints of being a GP 26. The boat is bloody well built as well!

#32 set321go

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Posted 13 September 2012 - 11:57 AM

What about something like the international Canoes have, I cant find a good picture but the top of the rudder had a box that contains the bearing, shaft and rudder, the whole box lifts out of the top of the boat.

Advantages: wouldn't need to change rudder or shaft
Disadvantages: No rudder when lifted, weight and strength potentially

I am not sure how well this idea would scale up to the loads on a keelboat rudder.

#33 Jim Donovan

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Posted 13 September 2012 - 02:54 PM

What about something like the international Canoes have, I cant find a good picture but the top of the rudder had a box that contains the bearing, shaft and rudder, the whole box lifts out of the top of the boat.

Advantages: wouldn't need to change rudder or shaft
Disadvantages: No rudder when lifted, weight and strength potentially

I am not sure how well this idea would scale up to the loads on a keelboat rudder.


I've used this style of rudder system on a 57 catamarn, so it scales up quite well.
It isn't particularly light and does not give you the ability to steer the boat at reduced draft.

#34 GybeSet®

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Posted 13 September 2012 - 08:42 PM

heres a twin on the very powerful and fast Open 7.50

in any case the rudder is a secondary issue relative to the lifting keel,
any of the above rudder systems, including a simple single cassette are proven to work on faster 8 mtr designs. The Fastest conventional 8.n mtr fully trailable design copyright terridodds.com


the keel is the big decision, to become a viable or 'real' alternative globally it must provide a tangible point of difference. Lifting all the way will enable true portability and "launchability"

#35 Heriberto

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Posted 13 September 2012 - 08:44 PM

What I was describing was this IC idea. Doesn't surprise me it has already been used. This is the system that I would go with if I absolutely needed ramp launching. Reduced draft steering isn't the problem, because you could steer with the outboard or even a (gasp!) paddle.

People want a swiss-army knife of boats. Can it have inboard diesel? Sleep 6 comfortably? Standing headroom? Come on. This is supposed to be a grand prix box rule 26 footer. It probably is reasonable to allow ramp launching features, as long as they don't let a camel nose under the tent to fracture an already fragile beginning.

#36 Ryley

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Posted 17 September 2012 - 02:29 PM

What I was describing was this IC idea. Doesn't surprise me it has already been used. This is the system that I would go with if I absolutely needed ramp launching. Reduced draft steering isn't the problem, because you could steer with the outboard or even a (gasp!) paddle.

People want a swiss-army knife of boats. Can it have inboard diesel? Sleep 6 comfortably? Standing headroom? Come on. This is supposed to be a grand prix box rule 26 footer. It probably is reasonable to allow ramp launching features, as long as they don't let a camel nose under the tent to fracture an already fragile beginning.


I hope you know I was kidding about the inboard diesel. I just spent the last 4 days moving rockit from boston (derig wednesday, haul thursday - steering with the outboard and the keel most of the way up), re-launch thursday night in CT, then reverse the process on Sunday). I completely agree that we're talking about a race boat, however there are going to be compromises. I have limited experience with cassette rudders, but the ones I've experienced have been nowhere near as strong or reliable as a transom hung rudder you can pull the pin on to get off the back. Likewise, a Quest 30 with a VARA system lost their rudder in moderate conditions and it was an expensive (and long) repair. I'm sure there's a good compromise in here.

#37 Heriberto

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Posted 17 September 2012 - 05:52 PM

In the last three weeks, two of my friends have lost rudders..... not a place to screw around.

#38 drdude

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Posted 17 September 2012 - 07:46 PM

I have been looking for the right boat for a long time and the GP 26 fits the bill. I need a lifting keel and rudder set up to launch from a hoist in Coconut Grove( 4.5ft at low tide), so when the design can be worked out I am all in. All involved have been incredibly informative and helpful (Jim Donovan, Windseeker, Kevin Farrar)
I've got to believe this class will explode once one or two boats with the right lifting keel and rudder design hit the US. I am looking forward to placing an order once the details are worked out. My vote would be to not take up the complete vertical dimension of the cabin with a trunk, and to lift the rudder similar to the Hendo without going to twin aft rudders. But I don't know shit, however, my check will clear.

#39 Jim Donovan

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Posted 18 September 2012 - 12:49 AM

I have been looking for the right boat for a long time and the GP 26 fits the bill. I need a lifting keel and rudder set up to launch from a hoist in Coconut Grove( 4.5ft at low tide), so when the design can be worked out I am all in. All involved have been incredibly informative and helpful (Jim Donovan, Windseeker, Kevin Farrar)
I've got to believe this class will explode once one or two boats with the right lifting keel and rudder design hit the US. I am looking forward to placing an order once the details are worked out. My vote would be to not take up the complete vertical dimension of the cabin with a trunk, and to lift the rudder similar to the Hendo without going to twin aft rudders. But I don't know shit, however, my check will clear.


This is exactly the information that will help us define the set-up.
I agree with your keel lift idea; I have this arrangement in my own 6m design.

There is a possibility that a few versions of rudder install could be available - this is a box rule and not a one-design, so the class allows this.
But I believe with some discussion, a solution that works well for everyone will be the standard "lifting foils" option.

#40 Steam Flyer

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Posted 18 September 2012 - 01:11 AM

shamelessly lifted from 'Donovan GP26 Starts Production In Turkey' thread




How is the GP26 to sail shorthanded (2-3 up)? When you say it's faster on W/L with 6-7 people over 15 knots TWS, then is it massively overpowered 2-up at that wind strength?


To quote what I posted previously,"VPP studies suggested that a heavier crew weight than GP26 class rule would be generally faster around a W/L track in 15 knots and above."
Essentially the GP26 4 person crew weight is too light for optimum performace in over 15 knots. 5 is better.
As the wind strength increases, and you need to sail upwind, extra crew will make the boat faster upwind.




Hmm... you mean, it's like almost every other boat anybody's ever heard of in that respect?
:wacko:

It's a better question to ask if the added crew/weight gains enough upwind to make up for the loss downwind, but as always it depends on the specific conditions. I'd guess that in flat water, crew weight upwind would be less critical.


A Gp 26 will be less over-powered with a short-handed crew of 3 than similar "powered up" sportsboats; the boat has a heavy bulb on a deep fin, and my design has a very stable hull form.
Would it be easy to sail a GP26 with 3 people in 15 knots or more?
A crew that small will need to be very, very good to set/gybe/take-down the spinnaker.


These are the kinds of answers I'm looking for... is it a boat that I can sail with a crew that I can reasonably expect to round up; two or three good sailors (most likely my wife will be one of them most of the time, very knowledgable but dislikes being scared) and whoever else is standing around when I say "Hey let's go sailing."

It's a beauty and must be a blast to sail, unfortunately in our area we need shallow-water capability. It's very exciting to think of this becoming possible!

FB- Doug


The hull's stability makes it much easier to sail than a Melges 24 by comparison.
New crew members will have an easier time getting used to the boat and not get taken out by the boom on the first gybe.

When the gust hits, the hull heels a bit and the heavy bulb at the end of the deep fin does it job remarkably well.
Added to this is an efficient rudder that stays immersed and will direct the boat wherever you want with little effort.
Forget spinning out of control and just hang on as the boat accelerates: :D

Have a look at the www.wraceboats.com website at the videos; check out the helmsman and what he is doing with the tiller - you don;t need much movement to keep this design tracking.


and the sailing photos we are getting back from Istanbul are just fantastic:


Curious what draft reduction would be needed?
Maybe this conversation would be better shifted to the current thread on that topic?


I have looked at the photos & most of the videos; it's noticeable that there is almost never any fuss coming off the rudder nor do the helmsman's veins bulge out with the strain of keeping a course. Personally I don't do much offshore racing however it would be really nice to be able to take the boat to (say for example) the Trans-Superior or perhaps the Marblehead-Halifax, both of which are sort of on my bucket list if I were to have one. Ibelieve the minimum length for the Chicago-Mac is 27' LOA to keep out MacGregor 26s...
:unsure:

Draft reduction- different needs for different folks. It seems to me that to go this route at all, it might as well be capable of pulling the keel bulb snug up to the hull such as other sportboats do for trailering... I would need to ramp launch it, and at least be able to motor out to deeper water with it raised fully. It would be really nice if it were liftable underway like the Tripp 26 or Elliott 770.

Other folks would rather not have the cabin trunk in the way; a stump-trunk & lifing gear that stows away would be fine and those who have a lift on a bulkhead don't really need to get the keel all the way up.

Dunno if that leaves a solution that works for everyone; maybe there's a clever way to engineer a sump-trunk combined with a C-section to the coachroof guiding the leading edge so it can be lifted underway, and a tackle on the main halyard or a removable L-bracket over the companionway or something to lift it all the way up for trailering.

I betcha there are also a number of folks who would be interested in keeping a boat like this on a lift behind their house on a small creek.

About rudders, I am less concerned. An outboard cassette has worked fine for years past; twins might be a good idea on a wide-sterned boat like this but the single inboard rudder seems to work marvelously.

FB- Doug

#41 Savage 17

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Posted 18 September 2012 - 02:02 AM

A Farr 30 has about 25% more waterline than a GP26. An early TP52, has 30% more waterline than a Carkeek 40 or similar class HPR40. In non-planing conditions waterline rules. Why is that concept hard to grasp in a sportboat forum? Fighting that battle every year with ratings committees. ORC also has a GP33 class. Would like to see a Mumm kick those. Don't get me wrong, the Mumm is/was a great boat, so were the early TP52's, but they won't plane or surf like a modern boat such as a Carkeek 40 or Donovan GP26.


Well, lets look at the age of the designs and the purpose of the boats. I have owned a Mumm 30 and it was my favorite boat. It would plane just like my Melges 24s that own currently. Is it as quick to plane no. Is it as violent, no. Did everyone on the boat have a smile on there face from ear to ear when they got off at the end of racing? YES!!!! Racing with 7... sometimes a pain, but have raced the boat with as little as 3 people. Hearing that the GP26 responds better to more weight is no surprise, just like the M24. Don't for get the Mumm was designed in 94-95. The M24 was 92, but purposely built to plane. The Donovan GP26 is what now 4 yrs old??

#42 Ryley

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Posted 18 September 2012 - 01:35 PM

Can we stop talking about Farr 30s on this thread? As far as I know none of them has a lifting keel or rudder. It doesn't matter how they perform against each other - some crappy rating system will make sure they're unfairly competitive, at least from one person's perspective. The only thing that matters is will a lifting-keel version of a GP26 be competitive against one that has a fixed keel. will the bottom be fair enough with the keel in the down position to match with the other GP's? Until momentum is fully built, I know people will be racing them phrf or irc or whatever, but the ultimate goal is to build enough mass for meaningful class racing, isn't it?

I want one. I don't know if I could ever afford one, or convince my 'accountant,' but this is the most exciting of the 20 - 30 footers for me. I can't wait to see some drawings of lift proposals.

#43 tamaozy

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Posted 18 September 2012 - 02:49 PM

+1

Can we stop talking about Farr 30s on this thread? As far as I know none of them has a lifting keel or rudder. It doesn't matter how they perform against each other - some crappy rating system will make sure they're unfairly competitive, at least from one person's perspective. The only thing that matters is will a lifting-keel version of a GP26 be competitive against one that has a fixed keel. will the bottom be fair enough with the keel in the down position to match with the other GP's? Until momentum is fully built, I know people will be racing them phrf or irc or whatever, but the ultimate goal is to build enough mass for meaningful class racing, isn't it?

I want one. I don't know if I could ever afford one, or convince my 'accountant,' but this is the most exciting of the 20 - 30 footers for me. I can't wait to see some drawings of lift proposals.



#44 midfleet

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Posted 18 September 2012 - 08:06 PM

I've been kicking around the idea of a GP26 since late 2008. The fixed keel was always the wall. If there was a lift keel option that allowed for ramp launching +/- 1 hour around low tide, the 26 would take off where I sail. A couple of us at the YC kicked it around about a year ago and the answer was the same. Needed a lift keel that drew 2.5 ft max and could be floated off the trailer in 3.5ft of water.

#45 Speng

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Posted 21 September 2012 - 07:20 PM

(1) keel lifts all the way up. Put a hole in the cabin top like an Ultimate 20.

(2) retractable/removable stocked rudder. Look at a Firebird 26 cat or Heriberto's pics in the other GP26 thread. None of the twin rudder or stern hung foolishness.

#46 Heriberto

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Posted 23 September 2012 - 03:08 PM

(1) keel lifts all the way up. Put a hole in the cabin top like an Ultimate 20.

(2) retractable/removable stocked rudder. Look at a Firebird 26 cat or Heriberto's pics in the other GP26 thread. None of the twin rudder or stern hung foolishness.


The only thing really missing from this equation is someone writing a check . Get on that Speng.

#47 arr4ws

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Posted 23 September 2012 - 03:12 PM

still have interest. keep us updated

#48 SA Lurker

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Posted 24 September 2012 - 02:53 PM

The only thing really missing from this equation is someone writing a check.


So what will it take? One enterprising soul to foot the bill for those waiting in the wings?

#49 Jim Donovan

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Posted 24 September 2012 - 11:48 PM

The design is in process; first step is to identify various options and address any compromises (there are a few).

I'd like to see the result that has the fewest compromises so the boat will be a fully competitive GP 26.

#50 tamaozy

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Posted 25 September 2012 - 01:56 AM

I guess given the extra crew that we have seen in the vids etc it can handle any extra weight, the issue will be the weight is in the wrong place. Does this mean a reduction in the bulb to keep the boat at minimum weight??? I dont know (some schmuck who just loves looking at these things, or sailing!!!)

I am sure that you will be able to work throught the problems Jim and come up with a great solution as you did in the original design.

#51 fullsail

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Posted 25 September 2012 - 01:58 AM

If it can help, here are a few photos of my cassette rudder. Inside the stainless tube are two Jeffa self align roller bearing. The tiller is light and very smooth. It is perfect for the boat.
DSC 4508
Album: superblanc rudder
4 images
0 comments



#52 Ryley

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Posted 25 September 2012 - 12:14 PM

If it can help, here are a few photos of my cassette rudder. Inside the stainless tube are two Jeffa self align roller bearing. The tiller is light and very smooth. It is perfect for the boat.

That's slick. How much does the whole assembly weigh? have you ever had any issues with the cassette, the fit, or any leaking or anything?

#53 fullsail

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Posted 25 September 2012 - 03:30 PM


If it can help, here are a few photos of my cassette rudder. Inside the stainless tube are two Jeffa self align roller bearing. The tiller is light and very smooth. It is perfect for the boat.

That's slick. How much does the whole assembly weigh? have you ever had any issues with the cassette, the fit, or any leaking or anything?


I can't say for the weight. The cassette is not much. But the rudder stock is 1 inch stainless and the rudder core is in plywood.
I have no issue at all with the kit. The cassette fit tight on the hole and stay there without the wing nuts. I keep the boat dry sail so I take out the rudder every time I use the boat. Many times a week. It is perfect.

#54 GybeSet®

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Posted 25 September 2012 - 08:49 PM

I guess given the extra crew that we have seen in the vids etc it can handle any extra weight, the issue will be the weight is in the wrong place. Does this mean a reduction in the bulb to keep the boat at minimum weight??? I dont know (some schmuck who just loves looking at these things, or sailing!!!)


GP26 is a class that includes weight in the measurements

why tf would you change it out of class ?

#55 TOTALXS

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Posted 25 September 2012 - 09:40 PM

The SR lne of boats uesed similar cassettes. I had one of the 2 SR25's and it was OK. I did something similar on my i550.

Posted Image
Posted Image

#56 tamaozy

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Posted 26 September 2012 - 12:20 AM


I guess given the extra crew that we have seen in the vids etc it can handle any extra weight, the issue will be the weight is in the wrong place. Does this mean a reduction in the bulb to keep the boat at minimum weight??? I dont know (some schmuck who just loves looking at these things, or sailing!!!)


GP26 is a class that includes weight in the measurements

why tf would you change it out of class ?


I didnt say change it out of class, you could happily add the weight to max class rules without losing a massive drop in speed from the numbers Jim was talking about. The problem as I see it, as I stated, is that you would probably have to adjust where the weight is carried which would mean it is not perfect weight.

Again, no design expertise here, just some schmuck who is interested to see how this problem is solved.

#57 GybeSet®

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Posted 26 September 2012 - 06:59 AM

.
I think you're expected 'problem' is a perceived one.

the published hull weight is at the lower end of the fairly tight weight range(of 10%) so there is room to include the extra feature of a trunk if it were added ( to the existing weight)
but it should not be needed, 450-500 odd kilograms (fairly apprx hull weight not incl keel) is ample to create a hull with a centreboard case
i say that as there are unrestricted 8 mtr sports down here that are as little as 180 odd kilo if you subtract the keel weight

the other factor is if the fin is in a case(trunk) then the Structure Weight low in the sump area that supports the present fixed keel can be used/sent somewheres else,
Also internal structures distributing keel loads are allowed to be made of carbon, which further mitigates weight differences
_____________________________________________________

on a separate note i just saw this in the rules

202 Appendages
202.1 Except for a single rudder located aft of the keel, no other moveable appendages are permitted.

so i suspect twin rudders are not subject to discussion

#58 Ryley

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Posted 26 September 2012 - 02:39 PM

Gybeset,
at this point if we went the two-rudder route, we would have to have the rules amended. The rules committee would probably make that change if it were in the interest of the class. I think at least two of the builders/sail makers are on the rules committee now.

I think though I'm liking the idea of a cassette inboard rudder - as you point out, the cassette/rudder post/blade assembly could easily be kept to minimum weights using carbon, and I'd be afraid that two rudders would make this boat very sticky in the light stuff, though maybe not.

#59 Savage 17

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Posted 26 September 2012 - 04:49 PM

My vote.... 1 rudder..... either similar VARA system that the Melges 32 has or just had the thing on the transom.....

#60 eerie sailor

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Posted 26 September 2012 - 07:31 PM

The VARA system rudder solves several issues: it allows for an inboard rudder location, and allows the rudder blade to be lifted and still steer the boat.
It is a relatively complicated system, not inexpensive, and I've heard a few complaints regarding bearings and movement in the system.

A single cassette rudder can be built as light as an inboard rudder, and it would take some on-the-water testing to determnine if it is as good a solution for performance as the inboard rudder.
The difference could be quite small.

Twin outboard rudders are quite good for windy reaching and running, and you might get away without cassettes as the rudders have about half the draft as the inboard rudder.

The information I have shows that the Antrim 27 keel does not lift completely; only 2.7 feet.
Is it possible to ramp launch an Antrim 27 with nearly 2.5 feet of keel sticking out from the hull bottom?

The only way to ramp launch an Antrim at a typical ramp is with a trailer tounge extender.

#61 eerie sailor

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Posted 26 September 2012 - 07:38 PM


What I was describing was this IC idea. Doesn't surprise me it has already been used. This is the system that I would go with if I absolutely needed ramp launching. Reduced draft steering isn't the problem, because you could steer with the outboard or even a (gasp!) paddle.

People want a swiss-army knife of boats. Can it have inboard diesel? Sleep 6 comfortably? Standing headroom? Come on. This is supposed to be a grand prix box rule 26 footer. It probably is reasonable to allow ramp launching features, as long as they don't let a camel nose under the tent to fracture an already fragile beginning.


I hope you know I was kidding about the inboard diesel. I just spent the last 4 days moving rockit from boston (derig wednesday, haul thursday - steering with the outboard and the keel most of the way up), re-launch thursday night in CT, then reverse the process on Sunday). I completely agree that we're talking about a race boat, however there are going to be compromises. I have limited experience with cassette rudders, but the ones I've experienced have been nowhere near as strong or reliable as a transom hung rudder you can pull the pin on to get off the back. Likewise, a Quest 30 with a VARA system lost their rudder in moderate conditions and it was an expensive (and long) repair. I'm sure there's a good compromise in here.

I've put over 20,000 miles on a VARA rudder system. I've had to repair it a few times over the years. But the repairs to both the races and other components have been pretty easy. Biggest issue has been wearing grooves into the races causing excessive movement or if not fixed soon enough, binding.

#62 Jim Donovan

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Posted 26 September 2012 - 10:54 PM

I haven't posted anything in a while on this topic - just taking notes at this time; keep the comments coming.

Anyone have a good idea how to put the rig up in a ramp launch scenerio?
I much prefer the keel stepped mast for rig stability in higher winds speeds; my experience with deck stepped masts are that they move a lot more in the lower panel.
I've been on a few boats where the deck stepped fittings have been completely inadequate.

#63 eerie sailor

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Posted 26 September 2012 - 11:19 PM

I haven't posted anything in a while on this topic - just taking notes at this time; keep the comments coming.

Anyone have a good idea how to put the rig up in a ramp launch scenerio?
I much prefer the keel stepped mast for rig stability in higher winds speeds; my experience with deck stepped masts are that they move a lot more in the lower panel.
I've been on a few boats where the deck stepped fittings have been completely inadequate.

Our keel is stepped below deck on a raised keel step. Our companionway hatch can be unbolted and removed which allows us to hinge the mast back towards the cockpit. It takes four of us to do this to a 45 foot tall rig.
Attached File  hentrail2.jpg   160.01K   54 downloads

With our handy dandy gin pole two of us can raise and lower the mast,
Attached File  GINPOLE 1.jpg   26.2K   52 downloads

#64 Heriberto

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Posted 26 September 2012 - 11:40 PM

I've always wanted to try using an extension ladder as a gin pole. I'm sure it would work fine and has other uses. Only thing is I've always needed a crane to put the boat in anyway.

#65 Steam Flyer

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Posted 27 September 2012 - 12:16 AM

I haven't posted anything in a while on this topic - just taking notes at this time; keep the comments coming.

Anyone have a good idea how to put the rig up in a ramp launch scenerio?
I much prefer the keel stepped mast for rig stability in higher winds speeds; my experience with deck stepped masts are that they move a lot more in the lower panel.
I've been on a few boats where the deck stepped fittings have been completely inadequate.


baby stays to just above the gooseneck? Dunno if this is class-legal but it's one way to stiffen up the lower panel on deck-stepped masts.

Another option is a removable panel in the coachroof, although the lift keel will be in the way so maybe it would need to be too wide to be practical.

I dislike gin poles because the usual method is to spend hours rigging & unrigging the "simple easy" gin pole & gear to raise the mast... but it does move the job from 'impossible' over to 'tedious & difficult'...

FB- Doug

#66 eerie sailor

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Posted 27 September 2012 - 12:51 AM


I haven't posted anything in a while on this topic - just taking notes at this time; keep the comments coming.

Anyone have a good idea how to put the rig up in a ramp launch scenerio?
I much prefer the keel stepped mast for rig stability in higher winds speeds; my experience with deck stepped masts are that they move a lot more in the lower panel.
I've been on a few boats where the deck stepped fittings have been completely inadequate.


baby stays to just above the gooseneck? Dunno if this is class-legal but it's one way to stiffen up the lower panel on deck-stepped masts.

Another option is a removable panel in the coachroof, although the lift keel will be in the way so maybe it would need to be too wide to be practical.

I dislike gin poles because the usual method is to spend hours rigging & unrigging the "simple easy" gin pole & gear to raise the mast... but it does move the job from 'impossible' over to 'tedious & difficult'...

FB- Doug

Our gin pole has two spectra shrouds and a spectra forestay and a 2:1 halyard (Nothing complicated0. From the time we hit the parking lot till we launch and lower the keel is about 1 1/2 hours. This is with two guys who know the drill well.

#67 TeamGladiator

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Posted 27 September 2012 - 01:23 AM

Look at the Cheetah 30 set up. 4 of us could go from freeway to sailing in 45 minutes (60 minutes if beer was involved).

Deck stepped mast with chicken stays just above the gooseneck.

Lifting keel was very slick but required some level of user understanding and mantenance.

14" draft with keel up. Easy on and off the trailer.

Negative was you CAN'T step the mast on the trailer. Boat has to be in the water with the keel down. But man did it dry sail easy from a ramp!

#68 rantifarian

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Posted 27 September 2012 - 05:18 AM

On the Beale 850 we had a deck stepped mast, took us about 1 hour to go from start to reversing down the ramp with 3 people.

We used a gin pole, but additionally had two poles that extended through the pivot point of the mast in the base. These stuck out horizontally, and served to stabilize the rig on the way up. Each had a line from the mast attached to the tip (we used small lazy jack lines, halyards could be used), and two fixed length lines with snap hooks to attach the poles to the trailer.
One person would winch the mast up if required, no helpers needed. I don't have any photos, but could probably sketch something up if required.

A similar setup could be applied to a keel stepped rig, if some work was put into the trailer design. Removing the helpers from the rig stabilization made the whole process much safer. Hungover helpers nearly cost us a rig

#69 Sandgroper Yachting

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Posted 27 September 2012 - 07:26 AM

This is the setup we are using on our Thompson 750.
The hinge point of the hydraulic ram is at the same level as the cockpit floor so raising and lowering the rig is simple.
As the rig is lowered back it can rotate on the ram to pass down beside the keel fin.

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#70 nroose

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Posted 27 September 2012 - 08:02 AM

I follow this design with interest but no money. My U24 has a small crane that consists of a tube that fits into another tube that is alongside the keel well, and has a little hand-cranked ratcheted winch on the top (looks sort of like one that might be on the front of a boat trailer to crank the boat in), so that it lifts the keel straight up, and leaves a foot or so of keel under the boat.

I personally like the idea of keeping the rudder where it is and having a cassette that is relatively small, like fullsail posted about. And yeah, you can steer with the outboard away from the ramp.

The boat looks great! But yeah, 6 people is a lot for that boat. I would think that the current GP26 owners would be open to small rules changes that allow retractable keel and ramp launching, but I would be surprised if they would be happy about 2 rudders.

#71 Ryley

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Posted 27 September 2012 - 08:11 PM

I haven't posted anything in a while on this topic - just taking notes at this time; keep the comments coming.

Anyone have a good idea how to put the rig up in a ramp launch scenerio?
I much prefer the keel stepped mast for rig stability in higher winds speeds; my experience with deck stepped masts are that they move a lot more in the lower panel.
I've been on a few boats where the deck stepped fittings have been completely inadequate.


how much does the mast weigh? we raise our tin stick on the elliott by using the pole and (fractional) spin halyards. I recently figured out that a bridle around the mast about 6' up tied to the stanchions match perfectly with our pivot point and that gives us the lateral stability until the shrouds kick in at near-vertical. Takes two people to raise it and 3 to drop it in this configuration.

But we're deck stepped and have a hinged deck plate. I could imagine this still working if the rig doesn't weigh too much, but a well-engineered gin pole that can be stored on the trailer is probably a better idea. then you can have one person crank the mast up, one to stabilize the foot, and one to guide it - probably could do it pretty easily with 3 or 4. One of the other "features" of the E770 rig is that you never have to disconnect the shrouds - only the headstay - when raising or lowering. This obviously won't work if you're sliding your mast 5' into a hole in the deck, but a reasonable, portable solution should be pretty easy to engineer, especially if the rig is as light as I think it is.

BTW, I *have* a boat where the deck-step fitting is entirely inadequate. we make-do ok though, but we don't generally sail in the conditions that a GP26 will handle.

#72 Ryley

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Posted 27 September 2012 - 08:19 PM

I follow this design with interest but no money. My U24 has a small crane that consists of a tube that fits into another tube that is alongside the keel well, and has a little hand-cranked ratcheted winch on the top (looks sort of like one that might be on the front of a boat trailer to crank the boat in), so that it lifts the keel straight up, and leaves a foot or so of keel under the boat.

I personally like the idea of keeping the rudder where it is and having a cassette that is relatively small, like fullsail posted about. And yeah, you can steer with the outboard away from the ramp.

The boat looks great! But yeah, 6 people is a lot for that boat. I would think that the current GP26 owners would be open to small rules changes that allow retractable keel and ramp launching, but I would be surprised if they would be happy about 2 rudders.


I disagree that 6 is a lot for a GP26. PHRF rules in NE would allow 6 and a crew weight of 1080 lbs. I doubt I'd want to (or need to) sail such a well-behaved boat with that many in typical Marblehead (read: drifting) conditions, but on the rare day it was necessary, I'd be very glad for the extra crew. We race RockIt with 5 because that's about as much room as I have, though *technically* we could go with 6.

As far as the two rudders, I think that the class probably would embrace it. Their single-rudder boats would be superior in light air conditions and they'd probably be equal in heavier conditions. What's not to like? However, I'm liking the idea of a drop-in cassette more as I look at it, though I'm guessing all this structural change will result in a considerably more expensive boat than the current fixed-keel/fixed-rudder model.

#73 Jim Donovan

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Posted 27 September 2012 - 10:40 PM

BTW, I *have* a boat where the deck-step fitting is entirely inadequate. we make-do ok though, but we don't generally sail in the conditions that a GP26 will handle.


Many years ago I had a memorable experience with a deck stepped rig:

Three of us were sailing a 23 foot trailer sailor up from Half Moon Bay to SF. We had made it about 2 miles south of the Golden Gate when the wind shifted dead-ahead and came in at a steady 25+ knots, kicking up a very nasty chop. It was particularly nasty because we had to pass only a few hundred yards to weather of Seal Rocks, which can have very strange wave backlash even on a nice day. I watched this flimsy deck stepped mast fitting flex and twist beyond anything one could consider acceptable. Why it didn't break must have been due to a lucky piece of stainless steel.

The instability of the mast step was't helping the mast much either, and it seemed quite ready to launch over the side at any minute.

A keel stepped mast gains a huge amount of support through the lower section, and it is my strong preference for sailing offshore.

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#74 Savage 17

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Posted 28 September 2012 - 05:23 PM

http://www.youtube.c...ayer_detailpage

#75 Icebear

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Posted 28 September 2012 - 07:08 PM

What was the total elapsed time of the A28 video?

#76 Ryley

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Posted 28 September 2012 - 08:43 PM

What was the total elapsed time of the A28 video?


I don't know about the A28, but with 3 people it takes a little more than an hour from the time we start derigging to being road-ready. That's taking the boom/vang/sails off, lifting the keel, getting on the trailer, getting the mast down, getting halyards stowed and the mast prepped for travel, and the straps on the trailer. it actually goes pretty quickly any more.

#77 Steam Flyer

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Posted 28 September 2012 - 08:49 PM


BTW, I *have* a boat where the deck-step fitting is entirely inadequate. we make-do ok though, but we don't generally sail in the conditions that a GP26 will handle.


Many years ago I had a memorable experience with a deck stepped rig:

Three of us were sailing a 23 foot trailer sailor up from Half Moon Bay to SF. We had made it about 2 miles south of the Golden Gate when the wind shifted dead-ahead and came in at a steady 25+ knots, kicking up a very nasty chop. It was particularly nasty because we had to pass only a few hundred yards to weather of Seal Rocks, which can have very strange wave backlash even on a nice day. I watched this flimsy deck stepped mast fitting flex and twist beyond anything one could consider acceptable. Why it didn't break must have been due to a lucky piece of stainless steel.

The instability of the mast step was't helping the mast much either, and it seemed quite ready to launch over the side at any minute.

A keel stepped mast gains a huge amount of support through the lower section, and it is my strong preference for sailing offshore.


guys, guys.... just because some deck-stepped masts suck does not mean they all do, nor that a deck-stepped mast must of necessity be poorly engineered.

I've seen crappy ones & good ones. Some of the better ones are fairly simple.

A keel-stepped mast does add control of mast bend low down, without the PITA of stays to the gooseneckor any such. Maybe the partners can be made like a big flanged socket with a matched pair of chocks that will lock the lower mast section in, yet be easily pullable.

FB- Doug

#78 Heriberto

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Posted 28 September 2012 - 10:03 PM

While that may be true, on a fixed weight boat, is it worth the weight in structure on the cabin top and bulkheads, rigging and fittings, (rather than lower in the hull) that is required to make a deck-stepped mast more reliable than a keel-stepped mast?

#79 Mojounwin

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Posted 28 September 2012 - 11:37 PM

I think it would be hard for a deck mounted rig to compete with a keel mounted rig on a GP26. Considering they are only a single spreader rig, alot of the lower end tuning would be achieved through the keel mount.

It's a shame they didn't make it more trailer friendly in the initial planning of the class. Such a small/light boat to be constrained by fixed keel/rig

Cheers
Mojo

#80 GybeSet®

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Posted 29 September 2012 - 12:37 AM

I hear ya Mojo but if the class doesn't ban lifting keels then I don't see anything that an innovative design couldn't overcome
i.e the mast has a minimum of 45kg that can negate the need for double spreaders

" weight in deck-stepped structure" ?
with good design and modern materials it arguably won't make a difference, or enough to transform into a performance difference

imo the current setup would need a strong deck anyway, or the advantage of a keel stepped mast would be compromised i.e. any movement at the deck flange and the advantage of a keel-stepper would be greatly diminished
A king post would weigh the same as the lost mast section did, a ring frame bulkhead could allow weight savings in the monocoque and grid etc

if the boat were being outrageously optimised to the nnth10 degree like a olympic or WC Starboat you could find another 900 grams of lead to place in the lower bulb to restore the CG, if needed at all

imo design could overcome it, notwithstanding that keel-stepped is the ultimate solution,

maybe Jim has to pull the off a design masterstroke with removable cutouts in the coachroof and a height solution that avoids interference with the centrecase whilst raising
giving similar 'raising' functionality to this

In the old 1/4 ton no rule/design hurdles were showstoppers, and this design is the 21st century version !

#81 Jim Donovan

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Posted 29 September 2012 - 01:08 AM



BTW, I *have* a boat where the deck-step fitting is entirely inadequate. we make-do ok though, but we don't generally sail in the conditions that a GP26 will handle.


Many years ago I had a memorable experience with a deck stepped rig:

Three of us were sailing a 23 foot trailer sailor up from Half Moon Bay to SF. We had made it about 2 miles south of the Golden Gate when the wind shifted dead-ahead and came in at a steady 25+ knots, kicking up a very nasty chop. It was particularly nasty because we had to pass only a few hundred yards to weather of Seal Rocks, which can have very strange wave backlash even on a nice day. I watched this flimsy deck stepped mast fitting flex and twist beyond anything one could consider acceptable. Why it didn't break must have been due to a lucky piece of stainless steel.

The instability of the mast step was't helping the mast much either, and it seemed quite ready to launch over the side at any minute.

A keel stepped mast gains a huge amount of support through the lower section, and it is my strong preference for sailing offshore.


guys, guys.... just because some deck-stepped masts suck does not mean they all do, nor that a deck-stepped mast must of necessity be poorly engineered.

I've seen crappy ones & good ones. Some of the better ones are fairly simple.

A keel-stepped mast does add control of mast bend low down, without the PITA of stays to the gooseneckor any such. Maybe the partners can be made like a big flanged socket with a matched pair of chocks that will lock the lower mast section in, yet be easily pullable.

FB- Doug


After my post about that terrible deck step, I recalled the number of boats w/deck stepped masts that sailed on in complete safety around those very same rocks, and in much worse conditions. Generally those rigs were quite large and stable, so any issues with lower panel stability were not an issue.

The GP 26 class minimum width is somewhat narrow, so IMO it will benefit from the keel stepped set-up.
Stays to the vang would help, but these add windage and can make spinnaker sets and take-downs more complicated.

#82 Jim Donovan

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Posted 29 September 2012 - 01:43 AM

The A 28 trailer is quite a nice arrangement that allows ramp launching with a keel that doesn't fully retract, which simplifies the keel "box" and lift arrangement quite a bit.
This would minimize the differences between a fixed and lifting keel.

#83 Mojounwin

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Posted 29 September 2012 - 05:07 AM

I'm just thinking out aloud and I'm not sure I can explain it well, but how about a deck stepped mast base that has no bottom. You raise the mast as you would a normal deck stepped mast, however once upright the mast can slide through the deck step and through the roof down to the cabin floor. You would need a pulley system to raise and lower the mast through the deck step and would also need an A frame structure to support the mast during all this. Everything going to plan you would have a keel stepped rig with that can be raised just like a deck stepped rig.

Cheers
Mojo

#84 GybeSet®

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Posted 29 September 2012 - 02:00 PM

great outside the square thinking, too bad about the extra spars

#85 Jim Donovan

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Posted 29 September 2012 - 02:56 PM

I'm just thinking out aloud and I'm not sure I can explain it well, but how about a deck stepped mast base that has no bottom. You raise the mast as you would a normal deck stepped mast, however once upright the mast can slide through the deck step and through the roof down to the cabin floor. You would need a pulley system to raise and lower the mast through the deck step and would also need an A frame structure to support the mast during all this. Everything going to plan you would have a keel stepped rig with that can be raised just like a deck stepped rig.

Cheers
Mojo


This concept is one I've been kicking around for my 6m, which has a Melges 24 mast that I've modified to be keel stepped.
Can't see why it wouldn't work for a GP 26.

Although I haven't detailed an design yet, I've thought an A-frame (similar to the Andrews 28 but attached to the trailer) would be set up to raise the mast high enough to
stick the lower end down through the deck and onto the step.
With a keel step mast there's no need to mess with the stays during the process - once it's engaged through the deck its stable.

Your comments have given me some additional ideas on how to come up with a very slick system that simplifies the process.
Not exactly a step w/o bottom - something quite different that does the same thing.

#86 Steam Flyer

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Posted 29 September 2012 - 03:19 PM

...

The GP 26 class minimum width is somewhat narrow, so IMO it will benefit from the keel stepped set-up.
Stays to the vang would help, but these add windage and can make spinnaker sets and take-downs more complicated.


Yabbut this gives the skipper another discipline option for keeping the crew under control... offenders get fed to the cheese slicer

I've sailed a couple of small boats with stays to the gooseneck and fouond them to be enough of a PITA to prefer not having them... OTOH if they serve a definite puprose & improve performance, wouldn't be a deal-breaker IMHO

Haven't seen the Andrews 28 in person but it looks like they've gotten a lot of things right.

FB- Doug

#87 fullsail

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Posted 29 September 2012 - 04:11 PM

Ok now, imagine a removable rouf and then an opening forward between the hatch hole and the partner the width of the mast. A cap can be bolted to cover the opening when not in use. So the mast can be planted directly to the keel and lifted like if it was on the deck.

#88 tamaozy

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Posted 29 September 2012 - 04:13 PM


I'm just thinking out aloud and I'm not sure I can explain it well, but how about a deck stepped mast base that has no bottom. You raise the mast as you would a normal deck stepped mast, however once upright the mast can slide through the deck step and through the roof down to the cabin floor. You would need a pulley system to raise and lower the mast through the deck step and would also need an A frame structure to support the mast during all this. Everything going to plan you would have a keel stepped rig with that can be raised just like a deck stepped rig.

Cheers
Mojo


This concept is one I've been kicking around for my 6m, which has a Melges 24 mast that I've modified to be keel stepped.
Can't see why it wouldn't work for a GP 26.

Although I haven't detailed an design yet, I've thought an A-frame (similar to the Andrews 28 but attached to the trailer) would be set up to raise the mast high enough to
stick the lower end down through the deck and onto the step.
With a keel step mast there's no need to mess with the stays during the process - once it's engaged through the deck its stable.

Your comments have given me some additional ideas on how to come up with a very slick system that simplifies the process.
Not exactly a step w/o bottom - something quite different that does the same thing.


I was thinking about having a large platform on top of the keel that the mast sat on once it was engaged. This way the keel lifting is part of lifting the mast to get it back to the deck level. Using an A-frame again. Only issue I couldnt get past was the boat would need to be in the water when the rig goes in or out.

Flame-on

#89 Heriberto

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Posted 29 September 2012 - 05:50 PM

Can someone explain to me how all of this is so much simpler than hiring a crane for a couple hundred bucks tops? I watched that Andrews 28 video and thought what a pain in the ass that all looks like.

#90 Jim Donovan

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Posted 30 September 2012 - 02:42 AM

And we've gone completely off topic with the mast stepping . . .
Back to lifting keels and rudders;

The concensus seems to be to have a keel that lifts as far up as the underside of the deckhouse, to avoid all the layout complexities of lifting up through the deck.
This allows the structure inside the boat to remain similar enough to the existing fixed keel that there would no notable difference in weight or performance between the two keel versions.

The rudder option that looks good is a "cassette" style, similar to those discussed above, but with the standard rudder and some very nice composite self-aligning bearings.
Again the weight differential compared the standard arrangement will be a few kgs, so we still ahve a fully competitive GP 26.

I have checked with the ORC and there willbe no issues with the lifting keel as long as it is fixed in the measured position for racing.

#91 Mojounwin

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Posted 30 September 2012 - 06:25 AM

Can someone explain to me how all of this is so much simpler than hiring a crane for a couple hundred bucks tops? I watched that Andrews 28 video and thought what a pain in the ass that all looks like.


It's much nicer when you can do it all yourself rather then having to rely on the crane operater to be around. Also starts to get costly if people want to travel around to various regattas. At $200 everytime you want to move the mast, to go away for a weekend regatta would cost $800.

Cheers
Mojo

#92 Steam Flyer

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Posted 30 September 2012 - 02:01 PM

Can someone explain to me how all of this is so much simpler than hiring a crane for a couple hundred bucks tops? I watched that Andrews 28 video and thought what a pain in the ass that all looks like.


So what are you griping about? There are plenty of fixed keel boats for all you guys who feel that way.
Then, when you want to go to a regatta, hire a crane at your end to get the boat ready to roll (and bribe friends/crew with beer for manpower) then hire a crane at the other end too.

As for my reasons
1- My sailing area is shallow
2- Out-of-water storage is much less trouble & expense
2a- hurricane prep on an out-of-water boat is much less time & work invested for a much more secure result
3- Even if your boat has a local one-design class, being able to travel to regattas is a big plus; adding a couple hundred bucks and most of a days work at each end is a burden few will undertake more than once a year (if then)

As has been pointed out, truly well engineered & well built hi-performance boats that can be traveled with (realtively) easily, and/or dry-sailed, are rare. Fixed keel boats are a dime a dozen.

FB- Doug

#93 Ryley

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Posted 30 September 2012 - 03:14 PM

And we've gone completely off topic with the mast stepping . . .
Back to lifting keels and rudders;

The concensus seems to be to have a keel that lifts as far up as the underside of the deckhouse, to avoid all the layout complexities of lifting up through the deck.
This allows the structure inside the boat to remain similar enough to the existing fixed keel that there would no notable difference in weight or performance between the two keel versions.

The rudder option that looks good is a "cassette" style, similar to those discussed above, but with the standard rudder and some very nice composite self-aligning bearings.
Again the weight differential compared the standard arrangement will be a few kgs, so we still ahve a fully competitive GP 26.

I have checked with the ORC and there willbe no issues with the lifting keel as long as it is fixed in the measured position for racing.


Will there be an issue regarding CAT 3 regs for keel boxes/"centerboard" trunks? Just curious what your take on that is.

#94 Ryley

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Posted 30 September 2012 - 03:23 PM

Can someone explain to me how all of this is so much simpler than hiring a crane for a couple hundred bucks tops? I watched that Andrews 28 video and thought what a pain in the ass that all looks like.

An hour and a half of rigging and derigging, vs. an hour and a half of rigging and derigging plus a couple hundred bucks tops? You tell me. RockIt goes in the water in May, travels to CT in June and September, out again (and maybe back, depending on the schedule) in October. That's about 7 round trips in 3 or 4 different locations. a couple hundred bucks each time adds up to a new sail a season that I could buy instead, or an extra regatta or two we could do . I don't think anyone on my crew would call me 'cheap' but that doesn't mean I don't have a budget.

I'd also point out that the Andrews 28 guys made that video pretty early on in their ownership. You do reach an efficiency after a a while - of course it doesn't get any faster, but it becomes so routine you don't worry about it. We figure we'll derig and haul to any regatta that would take more than 5 hours to reach by water.

#95 Jim Donovan

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Posted 30 September 2012 - 06:01 PM

Can we move this mast stepping discussion to a separate topic?
This is obviously a BIG subject to cover . . .

BTW; I totalluy agree that having a method to easily step the rig w/o a hoist or crane gives you a lot more options.

#96 Ryley

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Posted 30 September 2012 - 10:09 PM

Can we move this mast stepping discussion to a separate topic?
This is obviously a BIG subject to cover . . .

BTW; I totalluy agree that having a method to easily step the rig w/o a hoist or crane gives you a lot more options.


Ok, you mentioned orc being fine with a lifting keel as long as it is measured in the fixed position. what about Cat 3 regulation for:

3.0.2.2 Centreboard and daggerboard trunks and the like shall not open into the interior of a hull except via a watertight inspection/maintenance hatch of which the opening shall be entirely above the waterline of the yacht floating level in normal trim.


would a lifting keel be considered a daggerboard? or does that only include blades that are designed to be moved during sailing?

#97 GybeSet®

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Posted 30 September 2012 - 11:51 PM

I think 'bolted' in like the FT10 keeltop may be a sealed solution

otherwise its out through the coachroof !

It appears that the raked fin and its proximity to the mast (this design) makes the usual sportsboat solutions difficult,
where there is around a metre separation

Also raked fins on larger boats bind .. alot,
I've seen a raked 800kg keel Lidgard 29 bounced (kinda gently) on the hard off a travelift for 2 hours with no result, in the end it was 'left down' and fixed as it was a moored boat

less of an issue with lighter bulbs/keels, but straight up and down works better

#98 Heriberto

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Posted 30 September 2012 - 11:54 PM


Can we move this mast stepping discussion to a separate topic?
This is obviously a BIG subject to cover . . .

BTW; I totalluy agree that having a method to easily step the rig w/o a hoist or crane gives you a lot more options.


Ok, you mentioned orc being fine with a lifting keel as long as it is measured in the fixed position. what about Cat 3 regulation for:

3.0.2.2 Centreboard and daggerboard trunks and the like shall not open into the interior of a hull except via a watertight inspection/maintenance hatch of which the opening shall be entirely above the waterline of the yacht floating level in normal trim.


would a lifting keel be considered a daggerboard? or does that only include blades that are designed to be moved during sailing?


That is a good question, but I think any box which the keel fits into would have the top far above the waterline anyway.

#99 Jim Donovan

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Posted 01 October 2012 - 05:18 AM


Can we move this mast stepping discussion to a separate topic?
This is obviously a BIG subject to cover . . .

BTW; I totalluy agree that having a method to easily step the rig w/o a hoist or crane gives you a lot more options.


Ok, you mentioned orc being fine with a lifting keel as long as it is measured in the fixed position. what about Cat 3 regulation for:

3.0.2.2 Centreboard and daggerboard trunks and the like shall not open into the interior of a hull except via a watertight inspection/maintenance hatch of which the opening shall be entirely above the waterline of the yacht floating level in normal trim.


would a lifting keel be considered a daggerboard? or does that only include blades that are designed to be moved during sailing?


Arrangement will have typical sealed trunk with top above WL for Cat 3 compliance.

Lifting keel fin will not be raked.

This arrangement will definitely NOT be a "daggerboard" or keel fin which can be lifted during racing.

#100 TBone

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Posted 01 October 2012 - 09:11 AM

Performance consequence(s) to absence of keel rake?





Also tagged with one or more of these keywords: Lifting keel sportboat, Sportboat, GP26, Donovan26, Wraceboats

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