Transom Seam Leak

1994 SN Open-Bow

I changed out the rudder shaft packing and put the boat in the water to adjust the gland nut. While the boat was in the water I also adjusted the prop shaft packing gland nut.

While trailering the boat I looked at the inside rear of the transom and I saw water leaking in. The boat and trailer were on an angle on the launch ramp and the rear "seam" where the top and bottom halves of the boat join up was slightly under water. Based on that, it appears that the rear top/bottom seam at the transom is leaking.

I pulled the swim platform off and then I removed the rubber molding that covers up the seam. There appears to be a very thick and wide sealant (silicone?) under the molding. Upon closer inspection, there appears to be a 1/2" gap between the bottom and top halves of the boat that is filled in with this sealant. The gap is formed like an "over-bite" where the top half is 1/2" longer than the bottom half.

What are the suggestions for sealing the leak. I have a couple of tubes of 3M 42oo marine sealant. That is a big gap to fill and I was thinking of laying down a large bead of sealant. I spent an hour or so trimming back the old sealant and preparing the surfaces for a new sealant.

Suggestions? Comments?

JQ

Just finished sealing up the rear transom seam. Hopefully that will fix the "wet bilge" issue. I also discovered an area where water is coming in. When I installed a GPS speedometer, I removed the port pitot assembly. I originally filled up the screw holes and pitot tube hole with silicone. Bad move. I should have used 3M 4200. The silicone leaks. I removed the silicone and water came out of the holes. It is still dripping (1 day later) and so I'm letting all the water drip-dry before a fresh batch of 3M 4200.

I'll report back after next week's trip to Lake Powell to see how the repairs held-up.

JQ

I HATE SILICONE (in my Correct Craft, that is...)

OK, Pete. That will make 19 "hits".

JQ