New Ultralight Boatbuilding Method

[Antonio Bordeu]

I have a new Boatbuilding method. It uses composite materials, but in a very diferent way. I use urethan foam, very inexpensive and easy to work with. The method is frameless and very fast, you can save a lot of time, and you obtein an ultralight hull. Because it is really very revolutionary I like to obtein the experts opinion . You can see my method in my page www.magallanesboatbuilding.com.
Best regards
Antonio Bordeu.

[gonzo]

This method is well known. It is used with different variations. The problem with a brittle core is that it will fracture on impact causing delamination. Were your tests static only?

Dear Gonzo
You are right, the urethane foam is very brittle and you could have problems with the delamination. I avoid this problem using a round Hull. When you have flat walls this will be a problem. For this reason I don’t recommend my method for flat hulls. I use the radius-chine method.
I have been using my sail boat for the last 3 years, without delaminating problems. Even more, the last winter it stood up a very big storm, cut its anchor and crashed against the stones. The result was two or three hole but without delamination.
Best Regards
Antonio Bordeu

Before you make claims of "light weight", you need to compare different methods that provide the same strength.

Dave Gerr's scantlings are not intended to provide low weight. I have scantlings that do provide the maximum strength for a given weight, but I am too lazy to run the numbers.

I don't have access to your specific foam, but I suspect that due to the density you selected, you will have problems.

[gonzo]

I agree, what is the weight of the boat? A drawback is the loss of 10-12" of interior space. In a small boat that's considerable.

[Saltyredfisher]

Antonio I am very interested in using urethane foam. I am currently rebuilding a 20 Dusky center console fishing boat. And if there is a way to reduce cost and labor. Without risking strength. I am all for it.

[skiplistuser]

I had a friend who worked in the 1970's for General Motors (GM) as an interior designer for Corvette. They built a thick-skinned foam prototype car. They used a few plywood bulkheads to aid design and structure as well as a few metal-hard points mounted in the composite structure to mount the running gear. Much as the sailboat offered as an exapmle, they quickly carved out the design from glued-foam blocks. Reinforced foam beams built into the structure as well as relatively thick skins provided the strength. It was built by a few of the engineers and designers in a very short period of time.

The protype car had excellent acceleration, braking, and handling because of its light weight and aerodynamic shape. At the end of the evaluation period, they crashed the unmanned car into a concrete barrier at forty miles an hour. After the impact, a driver got back in the car and drove away. The car had two feet of foam in the front to act as a sacrificial barrier to absorb the energy of front impacts. Even the radiator was not leaking. GM had never had a car survive the frontal impact test until this protype did.

Similarily, a very strong boat could be quickly built out of thick-skinned laminates. Any needed additional strength not provided by the thick skin could be provided by foam beams that were laid up at the same time that the skins were laid up. They could even by infused at the same time.

I think this is an idea worth pursuing.

[Not A Guest]

I looked at your link.

You compare your glass over foam to Gerr's all glass.

How does it compare to Gerr's glass over wood strips?

[gonzo]

Gerr's formulas can use wood instead of foam as a core. It is heavier but stiffer longitudinally.

[jimcorliss]

You'll fin d this informative...

http://www.rqriley.com/frp-foam.html

Mechanix illistrated had a series of foam cored DIY cars..... the best being the turbo diesel centurion which used a kubota diesel in a triumph spitfire frame and got 128 mpg.... that would be sweet at todays prices , eayh ?

Jim

[Andy]

Hi Antonio - can you give us a progress report on your boat? How is she faring after a few years? Any further ideas to implement?

[kach22i]

Over time the foam may absorb as much as 3% water - out of the air, which will make it heavier over time. Not a big deal, some hovercraft are built this way.

Construction thread.....some models don't even use the wood stringers shown.
http://www.hovercruiser.org.uk/sevtec_scout.htm

[rwatson]

I would be interested in the breakdown of how it costs half as much as traditional methods.
Can you supply some facts and figures?

[Pericles]

Hello rwatson,

Check Antonio's profile.

http://boatdesign.net/forums/search....archid=1195127

I built a flat panel with 50 mm thick Foamglas http://www.foamglas.co.uk/ as the core and a skin of 850 gsm biax cloth on each side. It's 100% waterproof and for a small vessel, I think it might have possibilities.

However I'm not sure that Antonio's method is good for much more than a row boat. http://www.magallanesboatbuilding.com/ I can find only one post, although four are registered to his profile. That might be relevant.

Pericles

[rwatson]

Originally Posted by Pericles

Hello rwatson,

Check Antonio's profile.

http://boatdesign.net/forums/search....archid=1195127

Pericles

I tried that link - couldnt be found, but I am sure it didnt have dollar amounts and comparisons for different materials.

If it truly created hulls half the price, it might be worth using the technique for 'throwaway hulls'. get 5 years of sailing, build another hull etc.

It does irk me to see 'throwaway lines' like that, that promise so much, but come unsupported with facts.