Repairing crack on transom at the top of the transom knee

Builder's Forum
1

I built a Skua from a kit and mounted a 9.9 horse outboard along with SLT trim tabs.  The boat flies.  Recently, at about 20 knots, I hit some funky wake and capsized. 

I don't know if the force of the water in the cockpit against the transom when it inverted is the cause of this problem, or if it is the weight of the motor on the trailer.

At the top of the transom knee the plywood around the knee has cracked.  I sanded it down and can pull on the transom from the stern and see that the crack isn't superficial, but appears to extend into at least the first layer of plywood where it attaches to the knee.  It doesn't appear to extend into the other laminated layer of plywood, because it feels quite stiff and solid beyond that point.

I am contemplating laminating two layers of 3/8 Okume across the interior of the transom and fileting and bonding the piece to the knee and interior of the cockpit.  If anyone has encountered this, I am interested to know if you replaced the entire transom, or stiffened it in the manner I am considering.

2

   That transom delamination at the top of the knee is usually the result of an epoxy starved joint.  If you cut into the joint between the transom and the top of the knee to expose the volume where the knee is supposed to be epoxy bedded to the transom, you'll most likely find a void, which robs tthat joint of a lot of strength.  A solution that has worked on racing CCRs:  totally expose the voided area, mash in Cell-O-Fill thickened epoxy from one side until it oozes out the other side, don't try to make fillets yet, let cure until at least green, add healthy fillets to each side and over top of knee, also add glass cloth to the fillets.  I like to use two layers of 6-oz cloth, cut on the bias.  Easy fix, strong, and hardly noticable under the front of the engine.  A 9.9 really overpowers a CCR - expect more flips.

3

   Thank you OOTDB!