Design of hull

[bigjonny9]

Hi, I am a boat builder looking to design and build my own planning hull. I would like to know the fundamentals of hull design and what i need to take into consideration when designing my hull. the length of my boat will be between 5 and 6.5 metres (15-20ft) and trailable. thanks for any feedback

[Lurvio]

Why wouldn't existing plans work? Take a look at Glen L's site. They probably have what you need.

[daiquiri]

If you need to start from the fundamentals, then I agree with Lurvio's advice. Choose an existing design (there are so many nice designs around - nearly everything has been tried and done) and concentrate your efforts and money on building a well-designed boat. As about learning to design, it will take you at least 2-3 years and a lots of printed books (not internet forums) to learn the basics. It is not a short-term process.

[Gilbert]

You will want the buttock lines straight for at least the distance that will be in contact with the water while running normally. The center of gravity should be close to 1.25 times the waterline beam ahead of the transom. You can have either a constant deadrise bottom or a warped one, but if it is warped you don't want to have a lot of warp if you are figuring to run at high speeds. Other than that, I believe you can pretty much do as you please.
One of my personal preferences is that I think having the transom at the waterline somewhat narrower than the maximum waterline beam of the boat looks better than carrying the maximum waterline beam all the way back. The transom can be as much as 10 percent narrower than the maximum waterline beam without causing any harm.

[magwas]

I recomment the thread center of flotation calculation and implications?
The people in this forum (with the exception of Eric Sponberg) will never help you to learn boat design. I have already tried it and failed.

[sorenfdk]

Originally Posted by magwas

I recomment the thread center of flotation calculation and implications?
The people in this forum (with the exception of Eric Sponberg) will never help you to learn boat design. I have already tried it and failed.

Naval Architects in this forum have spent years in universities studying. It's just not possible to teach anyone how to design a boat here in this forum. Some people have a hard time understanding this...

It's true that Eric Sponbergs lectures on the different ratios etc. that many Naval Architects and yacht designers use are very useful. And it's also true that Eric is very friendly and willing to help anyone in need (he has helped me on more than one occasion, for which I'm very grateful!). But useful as they are, these ratios are only a little part of it. As a boatbuilder, you'll know that there is a whole lot more to yacht design that just establishing the main dimensions of the yacht (which really is what most of these ratios are for).

My best advice to you is to read some of the more recent books about yacht design. If you search these threads, you'll find a lot of them! I'll recommend Larsson & Eliasson's Principles of Yacht Design and Gerr's Elements of Boat Strength among many others.

If you have specific questions, then feel free to pose them here - there are many experienced and knowledgeable people here that are willing to help!