Strength of fiberglass

[Plainsman]

I'm going to mount a trolling motor on the bow of the boat. The glass there is mighty thin. The motor came with a metal mounting plate.

My question is, do I need to put some wood underneath the fiber glass for strength? Or is that what the plate, mounted on top will do?

 

[ondarvr]

Re: Strength of fiberglass

If you can get to the back side then it's best to use a backing plate, or at least large washers to spread the load.

If you can easily get the backside then adding glass would be even better.

 

[Plainsman]

Re: Strength of fiberglass

I do have a little mat and a lot of roven laying around. Do 1 then the other and repeat until it's what, 1/2 in thick?

 

[Boomyal]

Re: Strength of fiberglass

I do have a little mat and a lot of roven laying around. Do 1 then the other and repeat until it's what, 1/2 in thick?

IMHO Eric, it is hard to say without a picture, but I think it would be safe to say that whatever reinforcement you do, it should spread the load over the widest area possible. I've even done similar things using epoxy coated wood backing, peanut buttered to the back side.

 

[Yacht Dr.]

Re: Strength of fiberglass

What is "mighty thin" ? its only a TM..

Bolt it and forget it..if it takes a swim then try backing it with glass m8.. ( you should have a lanyard hooked to your motor anyways ).

YD.

 

[Plainsman]

Re: Strength of fiberglass

Thanks boom, it's about 1/4 in.
YD..well I'll hold my tounge...:|

 

[ondarvr]

Re: Strength of fiberglass

Anything will help, another 1/4" will work great and like Boom said, cover a large area.

 

[Plainsman]

Re: Strength of fiberglass

Thanks ondarvr!

 

[iwombat]

Re: Strength of fiberglass

If it were me I'd make an aluminum backer. Either out of flat stock, or sheet. One great big giant flat washer is better than 4 little ones.

 

[iwombat]

Re: Strength of fiberglass

You could then marine-tex nuts to the backside of the holes and make installation and later removal of the TM all that much easier.

 

[Yacht Dr.]

Re: Strength of fiberglass

Thanks boom, it's about 1/4 in.
YD..well I'll hold my tounge...:|

Why hold your tongue m8 ?

Im just saying..you said a TM .. so Im thinking a small electric troller ( about 20 lbs ? )

I dont really think its gonna rip out of the deck with its mounting plate,fenders and some 4200 on its own accord..

So Im thinking the only way that little bugger is gonna take a drink is by hitting something..now..IF you did hit something and the bug is mounted and bolted to your deck like a 200 HP merc then SOMETHING is gonna get hurt.. you choose..your troller..or your entire fordeck..

PS. 1/4" of glass is enough ( unless your hanging a 5 hp motor off your bow ) hehe..

Peace YD.

 

[iwombat]

Re: Strength of fiberglass

I'm guessing this is a bass boat. Whatever method you choose - once you stick it in the weeds or bang it up against that old snag while playing a fish, I think you'll be glad you didn't stick with 1/4 glass.

 

[Plainsman]

Re: Strength of fiberglass

Thanks for the replies guys. It's '76 fiberglass runabout.