boat design

I guess this would be a question for the experienced boat designers (claudio?) . What is the Cp of an IACC120 boat or do they vary with each individual hull and are you using a target Cp number for their design. Thanks all. Great site. Barry

Never mind answering question, answer was already on boat plans from Claudio. LOOK and ye shall find. But a question I know I can’t find an answer to, can someone start a new thread on the construction of sails from a to z, especially camber and on the squared head of the new generation of sails. I’m in the USA and will have to make sails for myself and will need plenty of info to make that happen. thanks again. Barry

Hi Barry,
I think that K1W120 and Astute Composites
are the most experienced persons to answer to your questions .
My speciality is hull design !

Hi Barry,

What I know about sail making you can write on the back of a postage stamp :lol: I’ve had a few attempts making my own sail board that worked reasonable well but their is quite a bit of “inside knowledge” not to mention “experince” required to refine skills in the art of sail making.

Gravitar (Canada) is making steady progress making with experince making his own sails & Astute Composites has the inside side knowledge and would be helpful …but the best A-Z advice to get you started is Ben Morris from Australia

This is the most comphensive information I’ve found to-date and Ben is very open in sharing information on the subject, just need to send him PM and he will readily help.

Cheers Alan

P.S I see Ben has added section on the “The Claudio Tool” as well, the old fox “Claudio” knows more about sail making than he is letting on :slight_smile:

try a search of the site - there has been a lot of discussion and posts. Seems redundant to re-post everything again. If something new - just add t the established thread. Thanks Dick

Amature sail maker here… I strongly recommend reading the Ben Morris site, it is my go-to site for a refresher for ever new set I make. Read, understand and feel free to ask questions. You have to decide how you are going to do your seeming, and where you are going to source your supplies. You also have to know that the first few attempts will be slightly ugly, but the boat will move. Feel free to PM me eh?


Hi Barry,

I have to echo Mike and say that the Ben Morris site has been invaluable.

You will have to put your balls on the line and just have a go.
All the advice we can offer will not be able to tell you how much luff curve to use or how much camber is needed.
This is because I understand that every mast behaves differently, and the sail + mast relationship is very important and can only be interpreted by trying and seeing the results for yourself. With some good video footage you can examine the sail performance during testing and begin to dissect the strengths and weaknesses of the sail cut you have. You then have somewhere to start from and you can move forward
Do not be discouraged, you can buy sails and still they will not work exactly as you would hope too. With this scenario you are working blind as sailmakers rarely submit the exact luff curve and draft tables with the set of sails you bought.

This is where being plucky and stepping out on your own leads you to great discoveries!
Some mistakes are obvious and others not so, but I could also be assuming too little…
Within 2 mains and 2 jibs you should have a setup that will not embarrass.
After that, as long as you do not play with extremes, it will be all about fine tuning.
Do not forget that the sail may be just fine, and your setting is off.
It’s catch 22. Study and digest. Post pics and get a second opinion if it’s a weird problem. Online, there is gold mine of info about sail setup too and before you know it you will be assessing the conditions and wishing you had the other main or jib rigged on your yacht!

Cheers, Jim