design verification

Olin Stephens spoke to my class at the Landing School in early 1991. I think people (I among them) were expecting him to talk about how to design a low drag, race winning hull shape. Instead he led off by saying (this is from my sometimes slippery memory):

There are priorities that ought to be kept straight when designing any vessel. The most important thing, it seems to me, is that a vessel be strong enough. The next most important is that it be stable enough. And a bit farther down the ladder, but still absolutely necessary, is that the craft be controllable. Everything else, drag reduction and what-not, must come after those three things, and a designer's time and attention should be allocated accordingly in all but the very rare case.​

Cyrus Hamlin's book (see my post #6 in this thread) continues the theme of priorities and the "design spiral".

 

The era (very unfortunately) of Olin Stephens is over. Nobody from the old guard can tell you how to design a today's winner.

Some of our US friends have pointed out - in different posts - that it is absolutely not necessary to be the inventor of the wheel again.

There are a few steps to begin with:


0) make sure that you have the required budget;

1) Fix your building material;

2) establish LOA and Bmax;

3) a sailing boat has several centers of gravity - check with a NA;

4) go for the maximum draft;

Look at the design of Ed Burnett mail@burnettyachtdesign.co.uk
that bring maybe some (expensive) ideas

 

I'm not sure on what basis D'Artois thinks Burnett is less "old guard" than Stephens, but here's a Burnett design that might be similar to what Fadgadget has in mind:
http://www.burnettyachtdesign.co.uk/112sloop.html

 

Stephen, Were you an instructor or a student at the landing school?
I don't think you can get much more traditional than ed burnett. Old guard? meaning long overhangs and beautiful proven designs? Anybody in here that thinks they can criticize sparkman and stephens should take a look in the mirror and throw away the computer.

 

D'Artois,
I'm not sure of this but I would venture to say Burnetts most profitable and popular design is the collaboration with Irens on a shoal draft coastal cruiser,"Roxane and Romilly", certainly the minimum draft.

 

Student.... design class of '91.
Full disclosure: Cy Hamlin, whose book I mentioned, was one of my teachers, and I worked for 3 months for S&S in 1997.

BTW many S&S designs are available from the Mystic Seaport Museum Library, where S&S sends them after a certain amount of time. Herreshoff's designs are held by MIT... I think it's called the "Hart Collection."

 

I was just curious. I live nearby and have some associates that are either graduates or graduate/instructors.
Please excuse the spelling, getting kind of late...
None of the people I know are currently working in the trade.

Good for you pursuing your education. Hope all is going well, be interested in your input for a design I have in the works. How's Hamlin? Any idea? Does he still live in Arundel? Do you suppose he would be intertested in critiquing an amatuer design?

 

I'm not making my living in the trade at the moment either. Just building a Classic Moth and trying to stay current. I have some thoughts of developing kit designs after I've raced the Moth for a while. I think I'll be happier designing on a small scale than trying to separate millionaires from their money.

In the late '90s Cy Hamlin took on a young partner. I haven't checked up on him since.

What's your design?

 

Steve,
It's an enlarged version of Irens Roxane, featured in woodenboat in 95 or so.
I understand what you say about the millionaire thing, however there's lots of us working folk looking for affordable cruising designs, I think Bolgers proven that.
Chandler

 

The Morris 36M seems to be the kind of boat you are heading toward although smaller. http://www.morrisyachts.com/morris36.html

There are a couple others that are new to the market and larger but I can't think which they are right now.

 

Well indeed tom 28571 it got to be something like the above mentioned yachts, but than completely different
That is a bit of the point to. There are so many yachts, with all different lines, forms and details, and they all sail very well.
And if you respect the hydrofysics and don't do crazy things,and if you compare your own design to that of others, I think you can't do much wrong in my opinion. But it would certainly help do have a little certainty of what you did is right, and that was the question ... So what things can help me verifing my design?

 

Engineering: Get with someone good. Alan Cattelliot at Multiplast would be an example near you. You could also take a look at software like HullScant <www.wumtia.soton.ac.uk/software.html> so you can work the tradeoffs yourself in the early going.

Hydrodynamics: Have an experienced person run several candidate hull/appendage combinations through free surface CFD software like Splash <www.panix.com/~brosen>, ShipFlow <www.flowtech.se>, or Michlet <www.cyberiad.net/hullsoft.htm>, and input the values into a proven VPP (velocity prediction program, basically an overall lift/drag sum-er/equilibrium solver) such as Velocity <www.schwenn.com> or WinDesign <www.wumtia.soton.ac.uk/software.html>. Raceboat designers who've already done this many times have an edge. Tops in Europe are Botin+Carkeek in Spain and Judel/Vrojlik in Germany.

On these process questions, Peter vanOosanen <www.oossanen.nl> is top notch (though as the final decisionmaking designer, his own designs haven't won much). You could also check with www.wumtia.soton.ac.uk, www.marin.nl, and other hydrodynamics labs.

Remember I said you can hire a designer as a consultant rather than as principal designer? Check out www.owenclarkedesign.com/default.asp?m=da&id=11201

America's Cup skipper Russell Coutts <www.russellcoutts.net/RC44/PressRelease.html> is apparently becoming a yacht designer. I suspect he knows a thing or two about optimization.

You could also purchase and learn to use CFD and VPPs yourself, but the time investment would be big. You should be able to hire someone to run multiple candidate designs for you for less than tank testing a single design. As I said before, finding a student who wants to put time into learning these programs anyway might be a good value proposition.

When looking at optimizing you should be very clear what the parameters are. The exact question you ask will have an enormous influence on the answer you get back.