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  #251  
Old 05-12-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

Cam,

I would dispute the beamy part! At 32.5', that is 2.5' longer than mine, and I am 10.5' wide! To me that would be on the narrow'ish side of things.

Marty
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  #252  
Old 05-12-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

Hartley:
I've been watching hockey (Go Leafs!) so I may be a bit brain dead but could you pleae explain exactly what you are talking about.

"Just sayin'"
Ok I get that part. Now "just sayin'" what?
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  #253  
Old 05-13-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

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Originally Posted by bobperry View Post
Hartley:
I've been watching hockey (Go Leafs!) so I may be a bit brain dead but could you pleae explain exactly what you are talking about.

"Just sayin'"
Ok I get that part. Now "just sayin'" what?
Sorry, Bob - I'm nowhere near as expert on rigging design as you are and didn't want to look like a smart arse..

Beamy bit: I noticed the LOA/Beam ratio from the dimensions Jeff listed wasn't alot different to my boat, so "plank on edge" it isn't. Fine.

I've had some discussion recently with a highly experienced sailmaker here, looking at how to increase drive and pointing ability of my boat. On a beamy boat like mine, with the rig I have, the genoa needs to be sheeted outside the shrouds. In this case, with the chainplates in the same relative positions, the headsail on a beamier boat naturally has a greater angle of attack than a really narrow boat with the same rig configuration and hence, inherently, can't point as well. For this reason, you want the shrouds to come inboard as much as possible whilst still supporting the mast - which is a compromise on side-loading - and this often means a smaller rig or beefier (heavier) mast and fittings than might otherwise be installed for other reasons.

Spreader angle/placement bit: By sweeping the spreaders back a bit on a single-spreader rig, the spreader tips can be placed so they don't interfere with the genoa leech sheeted outside - but on a 2-spreader rig it's a tougher ask because the 1st set is usually a bit lower and swept-back spreaders prevent the boom going right out - a compromise. Of course, the rig could be designed so that all of the headsails sheet inside the shrouds, but then they're more likely to hit the spreaders unless you choose smaller headsails with less sail area - another compromise.

My point was that there are many variables to consider in rig design and the deck plan (which we haven't seen yet) affects those just as much as the sail plan. I'm simply curious to see how you work all this.
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Last edited by Classic30; 05-13-2013 at 01:25 AM.
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  #254  
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Re: Bob Perry's take on Wolfenzee's dream boat

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Originally Posted by blt2ski View Post
Cam,

I would dispute the beamy part! At 32.5', that is 2.5' longer than mine, and I am 10.5' wide! To me that would be on the narrow'ish side of things.

Marty
Marty, lessee... By my calculations, your boat's LOA/Beam = 3.095, my boat = 3.272, this boat = 3.327 and, by contrast, the vital statistics of a 22 square meter in our fleet (Pastime II) with LOA = 42′ 10″ LWL 31′ Beam 7′ 10″ is 5.468! Now, that's what I call a narrow boat.

Anyways, my point still holds. Pastime II can climb to windward like a mountain goat, but I can't vouch for her comfort below decks... like I said, everything is a compromise.
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Last edited by Classic30; 05-13-2013 at 01:19 AM.
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  #255  
Old 05-13-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

Here is my take on the question of the rig and whether this is a beamy design or not:

The current version of the design is intentionally conservative. By intent it is neither beamy nor narrow. It is somewhat narrower than modern performance oriented designs and is a little beamier than some more traditional designs.

It is only 2" wider than Wolf's 1930's design, yet it has about 5% less deck area. The moment of that deck area is closer to 15% smaller than Wolf's boat, which means that this boat should develop substantially less form stability in the inverted position. Between the lower vertical CG, the higher freeboard and cabin volume(assuming that the cabin is reasonably tight to minimize downflooding) and the smaller inverted form stability, the new boat should should have a larger Limit of Positive Stability angle, and should require less force to re-right. But from my point of view, the much bigger gain is that the new design should have a lot more stability so it can carry more sail area in any given condition and have less drag allowing it to take advantage of that sail area. There should be big speed gains on all points of sail as well as under motor.

As to the rig, my original hope was to develop a rig that had enough sail area in its working sail plan (main and 110% jib) that genoas which lapped the shrouds would not be required. If that were the case, I would have liked to use a single spreader rig to keep the rigging simplier and easier to tune.

As it turns out, given the limits of the rig proportion on a boat with this high an L/D, that is not possible. In its current design, the rig will probably require a 135% or so genoa to achieve lighter air performance.

Once that became apparent, it also became apparent to me that Bob was 100% correct about this design needing double spreaders. At that point, the double spreaders allow a narrower width spreader, and shroud base, which should allow the headsails to have an entry angle that is consistent with the point ability that should be expected out the hull form and keel. My thinking is that the jib lead tracks would be located on the deck just outboard of the cabin trunk, and that the shrouds would be located just outboard of that.

I do want to point out that with raked back spreaders, the shrouds do not limit the position of the boom any more than the lowers would with inline spreaders.

Jeff
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Last edited by Jeff_H; 05-13-2013 at 10:42 AM.
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  #256  
Old 05-13-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

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Originally Posted by Jeff_H View Post
I do want to point out that with raked back spreaders, the shrouds do not limit the position of the boom any more than the lowers would with inline spreaders.

Jeff
True, based on boom angle, but swept spreaders have more effect on sail shape and the need for spreader patches/wear and tear concerns.

Having said that, though, we have a fairly strongly swept spreader rig and I don't find it a huge limitation. Ours is about the same sweep as our '80s Hunter 40 neighbour, not nearly so severe as that of the more recent Hunter B&R rigs. I think the spreader sweep angle such as on the B 36.7 is a nice compromise.

As you know, Jeff, I've kinda 'wished for' double spreaders on our rig (similar to yours - but our unsupported top panel is longer still) and I wondered if the stiffer, more stable support of the partners/two spreader points would help the support that upper panel more or not?? And of course there could be jumpers.... and on it goes...

btw.. this is a great thread and I for one would love to see the new and the old in a side by side test one day!!
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  #257  
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Re: Bob Perry's take on Wolfenzee's dream boat

Cam, Not sure what I am doing wrong, but if it is length divided by beam, I am 2.85, 30/10.5 = 2.85! if one is using deck length, 28.5/19.5 = 2,714285714 Still, I am about a foot wider and 2' shorter! Now the boat you mentioned is NARROW. I would still say this boat design is on the narrower end of things. Probably ave but narrow would be the better way to put it.

Marty
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  #258  
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Re: Bob Perry's take on Wolfenzee's dream boat

Sheeting angle and where you sheet to will involve the decision as to where to put the chainplates. Given we are a fairly beamy boat with a pretty modern ( relatively) underbody I would favor inboard chainplates and sheeting outboard of them. This would give the most versatility with genoa sizes. With double spreaders your ability to control the mast is increased. I do not think jumpers will be required at all. I would like to se the boat designed with a rig that could get us an AWA upwind of at least 32 degrees. I think Jeff's hull has this capability, comfortably.

Don't think Jeff has time to address a deck plan at this time and chainplate locations will be a function of interior layout, trunk width and bulkhead locations. So let's give Jeff the benefit of the doubt and proceed assuming that we can have a double spreader rig with chainplates just outboard of the trunk. This will give us clear side decks outboard and allow for a nice long genoa track.

Keep in mind that the choice of single or double spreaders is dependant on finding the right mast section. Today, as opposed to 20 years ago, most extrusions are proportioned for double spreaders. Boats like the Valiant 40, tayana 37 and Esprit 37 that riginally had single spreaders would all be better off with double spreaders. Decisions like that can't be made in an isolated way.
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Last edited by bobperry; 05-13-2013 at 11:41 AM.
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  #259  
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Re: Bob Perry's take on Wolfenzee's dream boat

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Originally Posted by SloopJonB View Post
I find Brent's Origami process fascinating and would really like to watch one of the hulls being folded into shape. Many of his points such as welding chainplates, cleats & stanchions down make a lot of sense. One of his boats would certainly seem to be a good choice for serious voyaging - the security of steel can't be denied. I'd also be interested in some info on the weight of his boats - that frameless monocoque construction has to save a bunch of weight.

Having said that, I DO wish he'd dial back the utilitarianism a notch or two and increase the "yacht" factor by a corresponding amount.
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Re: Bob Perry's take on Wolfenzee's dream boat

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Brent, I found this pic of one of your 12M's for sale. Is this the type of hatch you're talking about?

Used Brent Swain 12m for Sale | Yachts For Sale | Yachthub
Yes .I usually give it a bit of a cupola on top to increase the headroom going thru it. A greater angle also makes it easier.
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