Sailing Dinghy Design

[Stephen Ditmore]

The Moth at http://gregunit.tripod.com/cg/cg.htm
resembles Jim's 12 to my eye (though perhaps the Moth has more rocker).

[SailDesign]

Something's coming........

[SailDesign]

And it's got a looooong sprit (Dang! those things are obscene)
Anyhoo, this is where its got to so far. I would like to thank ALL of you I14-pimps for keeping me from productive work today. ;-)

[Pieetry]

dam! that soooo nice, when can i get delivery? does i come in blue? cant wait for the rig

[Tim B]

Why is it, that whenever I suggest a good idea, someone else gets there first!! I'll post my next design when I have time to draw it. However, I agree with Pieetry. That's a heck of a nice yacht!! I presume that it satisfies the hull station rule, does it also satisfy the bouyancy rules?

Cheers,

Tim B.

[SailDesign]

Pieetry - in order:- Thanks - when can you start building? - any colour you want ;-) - Soon, soon.....

Tim - it has to be because you post such goooooodd ideas. ;-P
Hull station rule OK, AFAICT, buoyancy should be good (haven't _actually_ checked yet) since it is drawn as a double-skinner.

I've been thinking about putting foils and the board, which would then have to become a daggerboard. Not exactly efficient in light air downwind mode, but could be tunable for alpha and position. Thoughts?

Steve

[Tim B]

I'm very flattered Steve. It's either that I have good ideas, or I'm stupid enough to post them before I've drawn the thing!! Well Done.

Um, yeah foils, yeah...

This is really an age old exercise, which I have done several times before. Does anyone know of a degree student in search of a project? Again, I can't really do much until the start of July. I am actually working on a project called 'Drag Reduction on Lifting Foils' which is basically an in depth look at this problem. When I've finished it (which should be at the end of July) I'll happily let anyone have a copy for a small fee. The project will go into much more detail than we need here. I'll also use the results to evaluate my '-Grid' suite of grid generators.

Cheers,

Tim B.

[Stephen Ditmore]

Nice 14, Steve!

Here's a photo of the winner of the "Classic" class among the Moths last Saturday:

[Stephen Ditmore]

Another photo of same. The design is based on "Mistral," and has a V shaped midsection that fairs connically into the rounded stern. Perhaps a third of the Classic Moths racing were also "Mistrals."

[Stephen Ditmore]

Another photo of same (just after a roll tack).

[Stephen Ditmore]

A Shelley between two Mistrals, and a vintage Moth to the right.

[SailDesign]

Nice Moths! I am glad to see no skinny little AxeMan-style boats in there. They may do well, but they are fugly as all get-out.

[SailDesign]

Well, this is where the rig is now. Bigger version of the same pic should be in my gallery when Jeff OK's it.

[SailDesign]

Well, just for fun, here is a zipped Rhino file of the 14 as of just now. Play, enjoy, tweak, whatever - have fun. I'll be playing, tweaking, etc at this end.
If those without Rhino want to play, let me know and I'll plonk an IGES file up here as well if i can shrink it enough.
Steve

[Tim B]

The one thing that concerns me slightly is the open transom. In order to work well, this means putting in a false deck, just above the waterline. This poses several questions. Firstly constuction, which is probably the smallest problem. Secondly weight (thin composites are not good in a flat sheet), and thirdly, as a by-product of the deck-weight, if we are to keep to a minimum weight that is already low, we need to put most of the weight into the hull laminate (giving a strength+stiffness advantage) and not so much in the deck. One other thought is that open transoms can be wet (especially if sailing backwards).

I'll have a look at that Rhino drawing.

Cheers,

Tim B.