Weird stringers and foam 67 Larson

[Ironpig]

So i got my boat back from my grandparents in B.C. and its resting comfortably in the garage. Pulled the floor up and found that Larson used fibreglass stringers with some foam here and there. The wood on top of the stringers which is 1"x10" wood is completely rotten. The foam which looked good at the start ended up housing a small portion of Shushwap lake, which is now on my garage floor. I feel secure in saying that i remove about 100 pounds of water from one stringer and the bow section. Still have one stringer to go. My question is this, I have to replace the foam(no pop bottles for me) and am wondering, since the foam held up the stringer at both ends and in the middle, what kind of foam should I use. I feel that 4lb may do the trick but i always sell myself on going the extra mile andd want to put in 8lb. Just looking for some examples of what others have used. I did the requisite search and have done nothing but read and have confused myself all over again. Also i want to completely fill the stringers and add a drain or weeping type pipe down the low side of the stringer. Anybody done something similar.
Pics will follow and thanks in advance for the help.

 

[oops!]

Re: Weird stringers and foam 67 Larson

a heavyer closed cell type of foam is right for what you need.....
talk to the marinas in sicamous.....there is a good one on the main street, not far from the public boat launch...(by the bridge)

as far as the pipe.....if you glass the area well you wont need it

cheers
oops

 

[oops!]

Re: Weird stringers and foam 67 Larson

sorry....where are you ?

sic or salmon arm?

 

[Ironpig]

Re: Weird stringers and foam 67 Larson

Me and the boat are in Calgary (land of no lakes) at the moment. Most of the fibreglass place recomend 2lb but I was thinking at least 4 to 8 lb for the stringers.

 

[oops!]

Re: Weird stringers and foam 67 Larson

the foam is just to give the stringers the shape. but i would go at least 4 lbs, as there is some structure in the foam. but.........

in a foam filled stringer, all the stregnth comes from the fiberglass around it.
so when you re foam them, make sure the glass is good.

cheers
oops

 

[Ironpig]

Re: Weird stringers and foam 67 Larson

The glass is really good. Now about stringer material. What should be used for these? I went to look for some cypress but near impossible to find in this part of the country. I need some 1" x 10" x 12 foot boards. What would work best?