Transom repair help

[ADQdory]

So after tearing the old motor off in preparation for the new, I have discovered that the problem I knew about was a little worse than I thought. Whomever had installed the old motor had over torqued one of the bolts and crushed the fiberglass on the inside of the transom, well over the years water has gotten into the core. I am replacing a small, 5"x5" square, section of one layer of the core and am wondering if it matters what kind of wood I use? I don't want to buy a full sheet of marine grade plywood for such a small repair.

[Sea Wolf]

ADQdory-

Hi!

Sorry about your problem!

If I only needed a 5" x 5" piece of plywood, marine grade, etc., I'd buy a door skin, which is about 1/16" thick, cut it into 6" x 6" squares, then laminate them together using a waterproof glue like Resorcinol or even epoxy resin, being sure to alternate the grain/direction of the wood, etc. Clamp well. Cut the 6x6 down to 5x5 after it sets up solid.

If you weren't sure Phiilippine mahogany would be dense enough to resist the compression, then go with a more dense wood, like Birch, or something else appropriate.

One could even alternate layers of fiberglass cloth (like thin deck cloth) between the layers of wood for added strength, but that might be overkill !

You could even build a laminate such as that above, layer by layer right in the space it's needed, but the glue-up would have to be planned out and the pieces fitted beforehand, then glued and clamped all at once.

Alternately, some supply houses will sell you a partial plywood sheet, like a 2' x 2' section, or may have a damaged sheet they will sell you a section of.

A marine repair shop would very likely have some small sections available from the sheets they use to repair boats, as well.

I like to make special lay-ups / laminates for projects on boats. There aren't too many things more beautiful than something laminated up of a dozen or more alternating layers of wood, finished naturally.

Good Luck!

Joe.

[thataway]

are you certain that water intrusion is involved with a single 5" x 5" section of the core?

[ADQdory]

To be honest I don't know if more of the core needs replaced or not. That was the softest spot and that's all I'm really ready to tear into right now. I would ideally like to replace the entire core with a synthetic core eventually, probably this winter, when I figure out where to get one. For now I'm just replacing this small section. I found some plywood used for concrete forms at work that I will use for this patch, since the concrete form doesn't absorb water.

[cbgale]

Concrete forms are sprayed with release agents, usually oil.

[rogerbum]

[AstoriaDave]

Probably find small sections of birch plywood at a craft store, or a woodworkers outlet like Rockler. Rockler is nationwide, probably locate a dealer off their web site: http://www.rockler.com/retail/stores

[A Fishin C]

a sheet of 3/4 std fir ply is around $30.00? encapsulate each layer separate then install.

[thataway]

With the knowledge that there is a good possibility that there is more water/bad wood core in the transom, I would take a chain saw to the core, and then a chisel and in a couple of hours at the most--the old core would be removed.

Only the wood is cut out from the top of the old transom, and all glass left intact.

Then pour in "SeaCast", and let it set up. If there is any fiberglass work needed, except non cosmetic repairs to make the transom watertight, do the cosmetic work next winter. One weekend with the SEaCast, and you have a lifetime transom. My concern with the Seacast is getting up to Kodiak, with freight costs.

http://www.transomrepair.net

I would also be concerned that anything --including epoxy would stick well to the concrete forms. My recollection was also some oil/preservative on forms--but that was a long time ago. To replace only a few square inches, does not make a lot of sense to me--because then you may find other parts of the old transom core failing during the summer.

[ADQdory]

I had not thought about any oils in the form board. I have looked into the seacast, but had a hard time finding a review here of anyone who had actually used it. I was also concerned about trying to get the seacast shipped here to Kodiak, I'm afraid the shipping would be almost as much as the seacast itself. I liked the idea of the seacast, but my only concern was that when/if I glass in the transom hole for the extension, is if it would be better to have one solid transom core rather than a pieced together one.

[thataway]

You are better with one solid core transom--in either case.