Foam / fiber glass t-top replacement for canvas

[krisnowicki]

The situation:
I got a 23 ft rabalo, nice beamy boat. I have redone the wiring and got her all ready to fish. The only thing I do not like about the boat is the T-Top is a little small (54" x54"). The canvas is also a little old. The top has running lights on top but no box or other electronics. The current T-Top has no curve to it, it is a flat 54 inch square.

The Idea:

I use the metal frame of the T-top to fasten a larger fiberglass top to the frame expanding the shade to 5x7 or 5x8. Thus plenty of shade for mahi fishing.

Using foam I will lay out a square 5x7 or 5x8, then put a 2 inch lip on it hanging down. Glass the top in using epoxy or poly resin and mat. The flip it over and build an built in electronics box, and then glass. like the top.

Once done, I will paint with 2 part expoy perfection.

Questions:
No one will walk on this thing, what is the thinest foam I can use as a core? or should I go plywood?

What oz matting and what kind of resin should I use?

Any ideas or suggestions?
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[krisnowicki]

Re: Foam / fiber glass t-top replacement for canvas

Any one have any ideas? I am thinking foam will be to flimsy I may go with plywood core. But I am worries about weight.

 

[Bondo]

Re: Foam / fiber glass t-top replacement for canvas

Ayuh,.... Yer only using the foam, as a form to glass,....

You can use Cardboard, 'n do the same thing....

The Strength will be in the glass, Not the form....

 

[krisnowicki]

Re: Foam / fiber glass t-top replacement for canvas

So do you think I will need epoxy or could I get away with poly? what ounce mat?

 

[robert graham]

Re: Foam / fiber glass t-top replacement for canvas

Sounds like a great project/idea, but remember to build it for 75MPH highway speeds, IF you trailer the boat...a flat sheet 5'X8' creates a lot of lift and stress on the structure at highway speeds. Wonder if you could find/modify a pick-up bed cover to work for your purpose?...should be about the right size/shape/stiffness? Good Luck!:

 

[krisnowicki]

Re: Foam / fiber glass t-top replacement for canvas

how would this cause more of a lift affect than a typical hard top found on a grady or pro-line?

 

[robert graham]

Re: Foam / fiber glass t-top replacement for canvas

how would this cause more of a lift affect than a typical hard top found on a grady or pro-line?

I'm just sayin', that for a home made top like you're describing, stiffness should be figured for highway speeds and not just for normal boat speeds. I have an 8'X8' wooden casting deck on the front of my jon boat and I've got it blocked and screwed down pretty darn tight, because at highway 75MPH it can create a lot of lift and buffeting. The floors in my boat are made from a very light but very stiff fiberglass reinforced foam board that would make a great top, but I'm not sure where to get this stuff or if it comes in larger than 4'X8' sheets. My boat is made by Express Boats...they might tell you where to get this stuff? Good Luck!

 

[oops!]

Re: Foam / fiber glass t-top replacement for canvas

we need pics.......

but.......a trick of the trade is to make a tubular frame........then stretch polyester fleece (sweat shirt material) over the frame.

the just coat it with poly resin....then add a few layers of 1.5 csm over it....

strong, permanent and you can even make it removable

 

[krisnowicki]

Re: Foam / fiber glass t-top replacement for canvas

I will post some pics tomorrow, but, strecthng fabric over it would not allow for me to expand the top size... that why I was thinking making a full sized fiberglass top