Transom math question.

[dude11]

I'm in the process of replacing a rotted transom in my 14ft.fiberglass tri-hull.Before I get in over my head;there was a soild 1" plywood one from the factory.I'm thinking two pieces of 1/2" pt ply as the replacement,and I guess the big question is --what to glue them together with,and what to use to glue it to the hull with??I had planned on wraping all the edges with fiber glass. Would you "prep" the ply prior to gluing?Kinda new at this stuff---does it show,lol.thax in advance,dude11

 

[geedubcpa]

Re: Transom math question.

One thing to think about - 1/2 inch plywood is sometimes slightly thinner than 1/2 inch. If you need to get to exact 1 inch it might take a layer of fiberglass or something.

 

[chargerboy]

Re: Transom math question.

Search the threads for transom replacement to see what other guys have done. Most coat the boards with epoxy and fiberglass, or resin and fiberglass.

 

[Woodonglass]

Re: Transom math question.

Be careful with using PT ply. The chemicals used can react with the fiberglass resin in a negative way. There is really no need to use it. Basic exterior grade ply uses the same glue as marine grade plywood only difference in the two is marine grade has no voids in the plys. Use OOPS Peanut butter to glue your two pieces together and to adhere it to your transom skin. (See OOPS post page 76 for his recipe) Your resin and glass will indeed increase your thickness so you might consider a 1/2 inch and 3/8 inch piece. with the resin, glass and peanut butter you should come out just about perfect.

Good Luck

 

[dude11]

Re: Transom math question.

So,I should do the glue-up,then wrap the whole thing w/fiberglass?I was thinking about sealing it with something then glassing around the whole border,glueing to the hull,then matting the face with about a 5" overlap to the sides,with maybe 2 or 3 layers build-up in the corners?Not good enough?Sure don't want to undergun here--it's my butt that'll get wet.dude11

 

[Woodonglass]

Re: Transom math question.

You would learn a lot by starting here and reading the next 10 pages
http://forums.iboats.com/showthread.php?t=365820&page=3:D

 

[bigredinohio]

Re: Transom math question.

I glued my wood together with PL Premium. I made sure it sat for a month, even though I thought it was dry then I used a v-notched trowel to spread the glue. Once the glue was spread and the wood together, I ran screws threw the wood into 2x4's on the opposite side to ensure that it was good and tight. Afterwards, fill the holes with filler and then I coated the wood with a couple of coats of epoxy resin then encapsulated the wood with a layer of epoxy and cloth. Lastly, I glued the wood in place using thickened epoxy (or peanut butter). From there, fillet, tab and fiberglass in place and I was done.

Is your motor an I/O or outboard? If it's an outboard, you could be better off going with (2) 3/4" and beefing it up. If it's I/O, then you probably want to keep with what you've got since the drives are so particular to transom thickness.

 

[Woodonglass]

Re: Transom math question.

Be careful with "Beefing up" your transom. If your top cap is sized then you will have a fitting problem. Make sure and check that everything will fit if you make it bigger.