I decided to drill through the transom for the wires from the fishing lights I'm installing. The cuttings from the drill came out nice and dry and I want to keep it that way so I contrived a way to seal the wood inside rather than just use a sealant on the exterior. I had used a product in the past from an outfit called Rot Doctor. One of their products is a 2 part epoxy sealer that is thin and will soak into dry wood as well as wet. I drilled 1/4 inch holes and got some 1/4 OD clear tubing. I put a piece outside and inside the transom and tied it up a foot or so above the hole. Then I put the epoxy in the tubing on the outside till it was 6 inches or so higher than the hole. It absorbed enough that it drew down in the tube almost to the hole so I topped it back up. It soaked up a little more but not much, maybe a couple more inches and has now stopped. It has a pot life of 4 hrs at 80 degrees so it should start to gel in another hour or so and I can pull the tubes and run the drill through again.