Stringer construction

Smokin'Mo

Seaman Apprentice
Joined
Oct 12, 2007
Messages
32
Has anyone heard of stringers made of outer layers of plywood, say 1/2" thk each side, with a layer of rigid foam board epoxied in between then capped on top and fibreglassed over to secure to hull?

I'm looking for the best method for replacing my boat stringers without all the weight. I have also heard that the foam board is easier to shape to the hull contour than solid wood. Once shaped the foam board becomes a template for the outer plywood layers.

Any suggestions?

Mo
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Stringer construction

best is 2 pieces of 3/4 laminated, with a 4 foot lap.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,468
Re: Stringer construction

Ayuh,........

Sounds like you're Over-Thinking,+ getting ready to Over-Build it......
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Re: Stringer construction

Either product (wood, foam) will work without the other one, so decide on which one you like better and just use it alone.
 
D

DJ

Guest
Re: Stringer construction

Either product (wood, foam) will work without the other one, so decide on which one you like better and just use it alone.

You could use foam as a core-no wood. You'll just have to put about twice as much glass on. Lay the glass mat on a bias.
 

drewpster

Commander
Joined
Oct 17, 2006
Messages
2,059
Re: Stringer construction

My engine stringers are wood core. The engine and transmission mounts sit on top of the stringers secured with lag bolts. The bolt threads are no longer holding and the stringers need replacement.
If I re-core them with foam securing the mounts will be a bigger job. Will the foam hold fasteners?
 
D

DJ

Guest
Re: Stringer construction

Will the foam hold fasteners?

No. You can glass wood in that area. Remember, any time you take wood out, you have to replace it with more glass than was there before. A lot more.

You could also glass in aluminum bolt plates. It all depends on how sophisticated you want to get.

I'm not a big fan of lag bolts. I know they are necessary, in some applications. If I have a way around using them, without too much difficulty, I do.
 

Robj

Lieutenant
Joined
Mar 22, 2007
Messages
1,441
Re: Stringer construction

Mine had the wooden block engine mount also. I changed it and used a piece of 3/8 thick aluminum angle and through bolted that to the stringer. I did increase the stringer thickness by adding another piece of 5/8 ply in the engine bay area for more strength. Did not like the lag bolt set-up. This arrangement I think is much better. Have also seen this type of set-up on other boats with much bigger power than mine, so it must be OK.

Have a great day,

Rob
 
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