foam filled stringers?

B

bocephus300

Well-known member
well im in the process of stiffning up my hull and want to fix my stringers. i see everybody keeps saying use this sea cast stuff. i have never built a airboat before but have worded on many sea- boats now-a-days all these boats use foam filled stringers. i have access to this type of foam. my question is can it be used in airboat applications or should i replace the wood?
 
i have talked to a boat repaier up here about the same problem, thats what he said he would have used and he said it was stronger than wood.. give it a try.....
 
if it was me,i would put wood back in their. you are talking about your and others lives that are around you and your boat. not only you alls lives bit the rest of your rigg like your motor.it is hard to get a motor off the bottom of the marsh when the foam don't hold up and your riggins fly out of the hull. if that foam would be a better option the hull manufactors would use it instead of wood!!!! just my 2 cents!!!!!!
 
I was thinking along the lines of cc, I dont see how the foam could be strong enough to hold the weight(and torque) of the engine, prop, rigging, and all the movement that comes with it. But... theyve got all kindsa crazy stuff these days and ive been wrong before :lol:
 
As long as the its done correctly, You are just as safe with the foam as you are with the wood. Most of the strength is gonna be in your glass work. I have had 2 boats we built with foam stringers and have never had a problem. If you feel uncomfortable with foam, there is a material we did one out of called (not wood) i believe. It is a recycled composite material that is light and you wont have to worry about it rotting once you drill the holes from your rigging into your stringers.
 
I used 1x4 clear redwood in all of our boats. Never used foam, but always wanted to try it. Our redwood sure didn't have much strength, you could break it across your knee easily. Redwood though does tend to resist rot. That's why I used that. On our stuff it held up to 455 DD Buicks with no problems.

If it has wood or rotted wood in them now, you are going to have to grind or cut them out to replace them anyway. I would replace with what was there originally unless you want to experiment.

Scotty
 
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well im not sure what is better my "wood" stringers i have now or foam? all the stringers look like that, it looks like when the hull was built they drilled holes in the ends of the stringers as a water apssage and never sealed them back up.
 
What jwoodlo1 said!!
The wood or foam is primarilly just a form
for the fiberglass which supplys the bulk
of the stength. Do a good glassing job with
with a heavy woven matt and I don't believe
there will be a nickles worth of differnce either
way. just remember to prep and clean everything
very good to get the best bond. and you'll never
get as good a bond as when the hull is laid up
and everything is curing at the same time, but
take your time, and don't take short cuts and it
will be fine. good luck.
 
i think im gonna go ahead and use the foam. i did a test and the foam dried pretty rigid and i plan on laying a few layers of mat across all the stringers anyways.. i just want to get every thing done so i can get this boat on the water!


i have ounce and a half mat.. is that gonna be a heavy enough mat? i have no experience in fiberglass, but i do in epoxies so im imagining its somewhat simmilar process?
 
also while on the subject of stringers and glass work... i plan on laying the 1 1/2 oz mat on the whole inside of the boat to stiffen it up and reinforce it a little better.. is that a finished product or do i need to cover it with a different type of mat/cloth?
 
Whoa, I agree with Nomad41, (seacast with fiber, or wood), with foam, when you tighten rigging mounting bolts, stringer will collapse partially and maybe crack fiberglass.
 
JUST TO LET YALL KNOW THER ARE DIFFERENT DENSITIES OF THE FOAMS, WE BUILD ALL OUR BOATS WITH FOAM STRINGERS AND IT SEEMS STRONGER THAN WOOD ONCE YOU GLASS IT IN THE RESIN SOAKS INTO THE FOAM AND ITS ALMOST SOLID FIBERGLASS STRINGERS THAT WILL NOT ROT. WOOD IS FINE IF YOUR ATTEMPTING TO DO IT AT HOME, THE FIBERFOAM BOARD IS EXPENSIVE,BUT YOU PROB WILL NEVER HAVE TO CHANGE A STRINGER, JMO
 
Use wood. 3 layers of 1708 than drill your mounting holes for your rigging. 1/2 inch fill that hole with six10 epoxy re drill to 3/8 and the wood stringers will outlast the rest of the boat , and cheaper than sea cast or coosa board.
 
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