DIY boat building?

[emf]

Hi, last year i built a small sailing boat, 5.5 metres proa. It was a really fun and fulfilling experience, I sailed it with IKEA shower curtains as sails .

Now i'm considering building something bigger, I understand the costs and difficulty would go up exponentially with size. Would a 15-20 metre (around 50 feet) motor boat be a feasible project? I'm thinking of building it in a country with cheap labour such as Indonesia or something in the South East Asia region, (I live in Singapore). What would be the problems with hiring people? What would be the main costs of a project like this? Anyone I could talk to in the region? What would be a practical budget? Any good books/ internet resources I could look at? Anyone have any experience with building in South East Asia?

Also, what are the problems with using an old car engine as the engine? If its well seperated from any water / sea spray would it not make a more powerful yet much cheaper alternative to a proper marine engine? Thanks.

[nero]

Can you post some photos of your proa?

A 15 to 20 meter motor boat. The hull will not be the biggest challenge. Fitting and finishing will be the expensive part. Cheaper alternative engines will be truck or tractor diesels.

[LostCause]

I think small block chevy and ford engines are pretty popular converted as marine engines. I don't have any experience with them though.

The Ryan Falconer V12 started out as two v6's welded together. It's definately been refined since then and is used in offshore powerboat racing. www.falconerengines.com

I think your biggest concern with automotive engines will be reliability. Auto engines aren't designed to be run at maximum rpm for any long period of time. You could probably blueprint and balance the engines, though. You'll also need to run a closed loop cooling system to prevent oxidation.

Automotive engines are definately an option, but they require more work to be a reliable and practical option. They aren't drop-in powerplants.

(I'd also like to see your proa...)

[emf]

Boat building here in singapore is virtually non-existant due to the lack of space. Even basic items such as lifejackets were extremely hard to find. And with that disclaimer...

Well the idea was to build a tacking proa which would sail closer to the wind when the outrigger is to windward and further from the wind when the outrigger is leeward. It started well with the hull designed in 3d max then exact dimensions copied onto the plywood. Then it just got more and more makeshift until the replacement outrigger was 2 pieces of foam and some bamboo poles tied together. Well, impatience and it being crewed by 3 17 year olds caused a great many capsizes. I was forced to stop work (came to the US to study) just as i started working out the problems .

We made a rather harrowing "voyage" to an island 5 km away. On the way back, a monsoon storm started and the boom rose to a 45 degree angle due to the lack of a kicker and half the outrigger broke off. Luckily we managed to get within 50 metres of the shore before the boat capsized due to the boom getting stuck half way thru a gybe. Needless to say all this could have been avoided with some patience, looking forward to going back to finish up this project.

The 4 shower curtains sewed together surprisingly held up pretty well even in strong wind. But then again its far from being the perfect airfoil... I'm thinking of reinforcing then tensioning the luff, noticed a huge amount of twist.

Anyway, the idea is to start planning for the next project which probably wont start till a few years time.

[nero]

Y'all know how to have fun! Why not put a second ama on it and make it a trimaran? Maybe use some 150mm pvc pipe as the amas.

Post some other pics when you get it to sail again.

[emf]

Yar, did that but failed to seal it properly and it got heavier and heavier till we had to cut it off... Will build a proper one out of plywood when i get back.

[frosh]

Hi emf, I sense a strong feeling of sloppy, hasty, thats near enough methodology in your Proa project.
If you are serious about building a 40-50 footer I think you need to rapidly get an attitude of being very serious about doing everything right, not rushing, and getting professional help, at least with the design, if not the construction phase as well.

[emf]

Indeed, impatience and excessive optimism nearly caused the downfall of that boat way too many times.

Anyway, I'm just trying to see if building a 15m boat with a tiny budget is feasible. What I have in mind is a basic 15m steel boat with a L:B ratio of around 5:1 or higher. The reason for wanting such a big boat is to provide enough space to live aboard comfortably for long periods. It would be optimised for efficiency with a crusing speed around 7knots. The powerplant would be a truck engine of around 100hp? Not including interior fittings/navigational equipment etc., what would be a possible budget should I design and build it myself.

My reasoning is that since I would simply be emulating a tried and tested design, it would be okay for me to design it myself (with much effort of course). By avoiding the large costs by designing it myself, not using a marine engine and hiring cheap labour in the region, would a budget of 15k USD be sufficient?

I understand this is ridiculously low by normal standards but steel is cheap, and the labour in the region is even cheaper. Sure it wont be the best looking boat, but with some resourcefulness and effort, is it feasible?

[emf]

Just got back from 2 weeks of sailing/building. Damn, Wichita feels even worse now. Anyway, I hope to be of some inspiration to the many posts I see about building their first boat or something. I think i'll call this project complete although i still have many ideas for next year . The idea was to build something which could go faster then the many lasers which sail near my house for alot cheaper. Well of course its a multihull and thus cheating but hey, i'm using a shower curtain as a sail.

I read frosh's post with interest, my project seems pretty similiar to his tacking proa, just a lot lousier. Finally got a proper outrigger built, the fun of flying the outrigger sure makes all the disadvantages worth it.

[ernie]

try tyvek for sails on the pora.

looks good.