HD sells this, which is similar if not the same as marine tex. I used to buy marine tex, but it is $28 at west marine, and Loctite is $6. I have used both on skiff repairs, seem identical to me. HD also sells a plastic version by loctite. I'd ask the pros at OEX first though, the crack is in a precarious spot.
http://www.homedepot.com/p/Loctite-0...5604/100371825