Boat design project-WARNING: AMATEURS AT WORK

[APA-168]

Hello all, this is a great forum, no wonder I keep coming back to it despite long lapses between visits.

I have been working for a while on a design project. I am a student working with a friend. For our senior year we are going to build a cruising sailboat. Right now, the plan is a sailing catamaran in the 30-35 ft range. That may change due to a lack of resources or time and we do realize how huge of a project this is. Working daily for several hours, since this will be in place of normal studying, we figure a full year from start to finish. We will be using unconventional materials and methods for construction, as yet undetermined.

Now for the disclaimer-we are both certified amateurs. I know a A LOT about boats and quite a bit about basic boat design, but I am NOT and don't plan on being a professional naval architect. We both have a great deal of hands on experience with engineering, have a bit of experience building boats, and a lot of experience doing "design." Of course, I put design in quotes since we are not really designing, just making pretty pictures come out of a computer program. Right now I am using Delftship to play around with, and have just download FREE!ship plus to experiment with next.

We are designing this boat with the singular goal of having successfully constructed a safe boat that can be sailed in coastal waters. WE ARE NOT AND NEVER WILL BE ABLE TO DESIGN A "PERFECT" BOAT. We are NOT racing this boat, are NOT selling it commercially and it is NOT to meet any specifications OTHER THAN OUR OWN. The idea is that if it satisfies us, it's good enough. It needn't please anyone else.

That said, I understand that there are some important issues that need to be dealt with, primarily for safety reasons which is why I am starting this thread. I want to know the most BASIC principles of small boat design. I realize that the only way to learn this is not to rely on computers, not to ask on a forum, but to read good solid literature or take a good course in boat design, preferably both.

To this end I would like recommendations on books. Specifically I want books dealing with how to use and apply the basic theories of boat design. I emphasize basic. Designing an efficient hull isn't very important, though some basic info is useful, so we don't design an unsailable slug. An efficient and safe rig is important. Stability is very important. Seaworthiness is very important as well.
I also want a couple of books that deal specifically with designing multihulls. How to apply above mentioned theories to designing mulithull sailboats.
Finally a couple of good books on sailing mulithulls. My only experience in sailing has been with monohull boats.

As I said, the best books for me are the ones that show me where and how to apply the theories. However, all recommendations are welcome.

Finally, any ideas and comments on my project are appreciated. If you want more specific info on what I am doing, please just ask and I will attempt to explain our motivations and ideas. As for design, I am sorry, I don't know anything more specific. We are in the very early stages of the process and right now I am just trying to get a handle on the MOST BASIC ideas and theories behind simple boat design. A lot is up in the air in terms of specifics. All we know is this:
-Catamaran
-Build in plywood
-Sailing
-30-35 ft LOA
-able to cruise for extended periods (a week or more)

I do apologize that my message is so long-winded just for the sake of making a simple request, but I felt it necessary. I have seen so many amateurs shot down by naval architects, rightly or wrongly, because either the amateur simply didn't know better, or the architect assumed too much about the novices intention. I repeat, we will not, can not, design the best boat. And that's ok. We can accept that. Now it's up to you experts to accept it to and if you feel so inclined, help us in our quest. Our goal is to sail, have fun, and do it safely.

Finally, if you see something amiss in my post in terms of facts, please let me know. I am young, excited and eager to learn as much as is reasonable. But please, don't simply call out errors and leave it. Please, if something is amiss, explain why it is wrong or if you can't point me to a resource that can.

Thank you all so much for your time.

[Elmo]

"THE CRUISING MULTIHULL"

By Chris White, 267 pages.One of the best selling books ever about cats and tris. Tens of thousands of copies sold.
No "fluff".

[sabahcat]

What sort of boat?

Fast ply

Double Diamond
http://www.givencats.com/


More comfortable ply

Easy 10.2
http://easycatamarans.com.au/

[sabahcat]

Originally Posted by APA-168

We will be using unconventional materials and methods for construction, as yet undetermined.

Why?.

[APA-168]

Thank you both for your replies.

Sabahcat-sorry, those were two issues I forgot to address. First, comfortable ply is the order of the day. Cruising comfortably is our primary focus.

Second, primarily due to limited resources. We will not compromise on strength where it counts, but we are thinking about alternative (ie cheap) materials for things like the superstructure/cabin, I will repeat that anything that is necessary for safety will not be compromised on but where ever we can get away with alternative materials we will. This issue is the subject of a lot of ongoing research on my part and could easily be a whole 'nother thread.

[sabahcat]

Have you looked at these materials?

http://polycore.com.au/

http://www.highpointtimber.com.au/pr...pplanking.html

[APA-168]

Very very interesting, thank you for those links. The first one especially is interesting. In your opinion (or anyone else's for that matter) would any of their products be suitable for structural applications in a boat of this size? I don't have time to go over it all right now, perhaps the aluminum honeycomb material could be used.

[sabahcat]

[quote=APA-168;325910]Very very interesting, thank you for those links. The first one especially is interesting. In your opinion (or anyone else's for that matter) would any of their products be suitable for structural applications in a boat of this size?

Pic on homepage

I don't have time to go over it all right now, perhaps the aluminum honeycomb material could be used.

why?

[APA-168]

Sorry, by structural applications I meant the frames/bulkheads etc. My fault for not using correct terminology...

[sabahcat]

They use poly prop honeycomb, balsa, foam, ply drum for main BH's now on very large vessels

Why would you want to complicate things and add additional expense by using aluminium honeycomb?

To borrow from Roger Simpson, a designer I have great respect for having worked built a 32 footer and now doing a modified 50fter from his designs

APPROPRIATE TECHNOLOGY
You may have gathered by now, and certainly should do by the end of this brochure, that we are in love with practicalities. We do not eschew technology but for us it must serve a purpose and it should, in the technocrats words, be user 'user friendly'.

As an example, today's epoxies are designed by highly qualified and skilled chemical engineers. They have, bless 'em, made them easy and available for us to use. All you do is mix them together in the correct proportions ... they even supply accurate measuring pumps to make sure you get it right. What happens to all the cute little molecules as they busily cross link? Who cares all we need to know is when they've done their thing we've something that's damn strong and will hold our boat together for many years to come.

Therefore, our definition of APPROPRIATE TECHNOLOGY, would run something like this. It is the use of technology to achieve a result that is appropriate to strength, quality, end usage and economics.

http://boatcraft.com.au/simpson.html

[APA-168]

I don't really I just wasn't sure if the other stuff was strong enough to be used for primary structural support. Very interesting material, obviously I will have to look into. Will probably end up using it in some way.

Thanks for your help on this, it is really appreciated! Just out pure curiosity, whereabouts in Australia are you from? I have grandparents living in Brisbane. Visited there a couple years ago, very nice city, considering it was Queensland and all

[sabahcat]

Originally Posted by APA-168

Just out pure curiosity, whereabouts in Australia are you from?

Brisbane

[APA-168]

Originally Posted by sabahcat

Brisbane

Indeed? In all seriousness, it is a very nice city and of course the people were absolutely wonderful. I still believe that the Aussies are among the most friendly people on earth. My relatives absolutely love it there. I also have family living up north, Townsville area. Also a very nice area.

In any case, back to the subject at hand. Thanks for that other link seems to have a lot of good information as well as some beautiful boats.