Transom Re-Build Check List...

[Islandtrader]

At the end of the month I will be getting some free labor (son-in-law). Good time to get my transom done. After reading a lot of the posts here on transom re builds here is my check list.

Prep plywood with epoxy (slow cure and 10% acetone).

Epoxy PW cores to each other.

1 layer 1708 to PW core (inside face).

1 layer of 1708 to inner transom skin.

Epoxy and bed transom core to inside of transom skin.

Tape new transom core to sides and bottom. 12" 8" 4".

Does this look about right?

Please feel free to add or subtract to the list. I have a few weeks to prep and to get everything ready.

Thanks a bunch.

[Bushwacker]

Terry - saw Skip and Carla tonight and reviewed what we did on their 21's transom, and there are a couple of things you may want to add to list. When you say bed core to transom skin, I assume you mean coat the transom skin with cabosil, troweled to create "V" grooves in it. We also put some randomly spaced holes in core to allow air to escape, per recommendations from Dan of Fiberglass 1. Seems like the air bleed holes were about 3/8" in diameter, but you may want to confirm that with Skip. You may also want to have some provisions for clamping the core to transom skin until the cabosil cures. Also need to wash off amine blush on any epoxy coated surfaces that have cured overnight. Otherwise your list looks pretty good. Denny

[Islandtrader]

Thanks Denny on the holes...I forgot about that. Clamping was a given.

What I meant by epoxy and bed was, I will use a 2 different products by System 3. One being gelmagic (pre mixed cabosil)that will "glue" the core to the transom. Second product called Silvertip EZ fillet. The core will be set into it (sides and bottom), then I will fillet the edges, and have a nice radius to lay the cloth over.

Anybody else out there have any thoughts?

[1bayouboy]

Did the 1708 have a layer of 3/4 mat?? If so was was it against transom and PW core? Is mat needed between layers of 1708??

[Bushwacker]

Yes, the 1708 had mat on one side. Not sure if it's absolutely required but it probably can't hurt. As I remember, the mat side was always put up against the previous layer, starting with original transom skin. We used 1.5" Coosa board core instead of plywood. Used cabosil for both bedding and fillets around edge of core, radius about size of a quarter. I believe we used 4 layers of 1708/mat on both sides of the core, with all layers wrapping around into bottom and sides of hull; I think first layer went about 18" forward of transom, with each subsequent layer a couple of inches shorter than previous one. You can check Carla's original post for photos and more details. Resulting transom is at least 2" thick . . . should be plenty stout enough to handle either twins or a big single! Dan also recommended using SS or bronze sleeves on all engine mount bolts so that sleeves would take most of the compressive bolt load, allowing the glass & core to take primarily shear and bending loads.