Building a boat from Urethane Foam

[Mark42]

Found a website where a 33 foot sailboat was built by using urethane foam pannels glued together over a simple wood frame, then covered with a 1/4" of 'glass resin on both sides. The wood frame is only used as a "male mold" form the urethane pannels over. After glassing the outside, the mold is removed and the inside is glassed over too. <br /><br /><br />

<br /><br />The foam is about 4 inches thick and a 15" by 58" piece with glass supports up to 1700lbs before it buckled. <br /><br />Check out this site and let me know what you think. <br /><br /> magallanesboatbuilding

 

[ondarvr]

Re: Building a boat from Urethane Foam

A new method that's been around since day 1. I didn't look for a date on his site, but if it's after 1960 (sarcasm) it's all been done before. Not that it's a bad way to make something, it was just kind of odd that he claims it's new.

 

[Mark42]

Re: Building a boat from Urethane Foam

I think it's basically surf board technology. I was wondering if I could get a 20'x12'x8' block of urethane foam and carve a boat out of it.

 

[ondarvr]

Re: Building a boat from Urethane Foam

Some tooling is made in a similar way, only the foam is CNC cut and then glassed over, or it's used as a plug.<br /><br />Just get the same size block of fiberglass and grind off everything that doesn't look like a boat. Then you don't have to get your hands sticky or smell up the house with resin.

 

[Mark42]

Re: Building a boat from Urethane Foam

Is it a proven safe method of building a boat. I have this idea of building a "stitch & glue" boat using 4" thick foam planks. In stead of using plywood as the base, transfer the templates/measurements to foam pannels and assemble that way. <br /><br />I could imagine that a boat built from foam pannels would be unsinkable. Some ply would be needed in the transom. The stringers would be foam too with plywood floor, or no stringers and solid foam floor.<br /><br />Kind of a fun idea.

 

[Bondo]

Re: Building a boat from Urethane Foam

Kinda like a Home Made Boston Whaler.......

 

[fishingdan]

Re: Building a boat from Urethane Foam

Originally posted by Mark42:<br /> Is it a proven safe method of building a boat. I have this idea of building a "stitch & glue" boat using 4" thick foam planks. In stead of using plywood as the base, transfer the templates/measurements to foam pannels and assemble that way. <br /><br />I could imagine that a boat built from foam pannels would be unsinkable. Some ply would be needed in the transom. The stringers would be foam too with plywood floor, or no stringers and solid foam floor.<br /><br />Kind of a fun idea.

There is no reason one couldn't do that, but the fiberglass laminations need to be carefully considered. The homestore foam panels have no strength. <br /><br />You must compensate for that with more fiberglass (and that means more epoxy) than one would use if they were using a plywood core. An alternative would be to use structural foam panels designed for this purpose. The downside is that they cost as much (or more) as high quality imported marine ply.<br /><br />If you try this, I would try it on a dingy design or some other displacement hull. A planing needs to be much stronger (in the right ways). <br /><br />The truth is that it is very difficult to find something with the strength to weight ratio of engineered wood (like plywood).<br /><br />Just some thoughts.

 

[BillP]

Re: Building a boat from Urethane Foam

Like already said, the guy didn't invent anything. He just came to the party after everyone went home and believes he is the first to arrive. This was being used in the late 1960s for oil platform lifeboat construction. They used shaped solid blocks with very heavy chop over it all to make a bullet proof hull.<br /><br />Anyway, if you are building foam in flat panels put stringers in the foam. It's surfboard technology from the late 1950s and still in use today. Cut the foam sheets lengthwise (or whatever) and glue them back together with a wood stringer in between. Even gluelines give impressive strength. Most surfboards use wood from 1/8" birch, redwood, fir for up to 1" wide and balsa up 2" wide. They use standard polyester resin (pigmented to give a colored glue line) to glue them together and it holds fine. The same methods could be used on flat foam panels in boats. Plywood could be used. Take a 1/4"thick x 3"wide plank of ply, turn it on edge and try to bend it. Super strong.

 

[otterbfishin]

Re: Building a boat from Urethane Foam

Lots of Foam Boat stuff here:<br /> http://www.refugeforums.com/refuge/showthread.php?t=353711

 

[Mark42]

Re: Building a boat from Urethane Foam

otterbfishin,<br /><br />Thanks so much for that link. Its nice to see people actually do use the home depot foam for more than insulating a house.<br /> <br />The guy who made that ice boat really did a great job, really gives me some inspiration to make a cruiser.<br /><br />I'm going to look in the yellow pages for foam suppliers and see what is available in various densities and sizes. <br /><br />I'll keep you posted.<br /><br />BTW, If anyone has any links to people building boats from foam, please post the links.<br /><br />Thanks,<br /><br />Mark

 

[otterbfishin]

Re: Building a boat from Urethane Foam

Mark42,<br />From my research into foam boat building it seems that it is most suitable for small boats. I have come across information that suggests that the epoxy glass/foam joint tends to delaminate at stress points, and that extra glass is needed to support these parts of the structure. This info suggests that the resulting hull is not that much lighter than a plywood core, and allot less strong. Be worth while doing lots of research before spending big bucks on materials and labor. Working with foam is also very messy as the foam dust seems to be electrostatic and sticks to everything. The easiest way to shape it is with a power planer, but you need to cover the air intake to the motor with something to prevent the foam dust from burning up the motor. Lots for you to look into.<br />Good luck and keep us posted as to your findings.<br />Otterbfishin

 

[bayman]

Re: Building a boat from Urethane Foam

That's a big boat to make with this method I think. One really good hit on a rock witha boat this large and things might not look too good.