Dear Laser sailor,

Used Laser hulls are cheap and plentiful, and CB trunk repairs are difficult. Consider getting a 'new to you' hull. They are all over craigslist. Free to $2000 depending on thier age.

That being said, first confirm that the CB trunk is the culprit. Remove and Recaulk the stern plug and the set the boat in calm water. Did she leak? No, the problem is elsewhere - rails, maststep... 

Yes, then the proper way to repair a CB trunk leak is from the inside of the boat. You can fill holes with thickened epoxy in the trunk cavity, and this will stop a leak but not add much strength. Next time sailing in breeze and the board loads up with pressure the epoxy repairs will crack. The proper way is to cut inspection ports in the deck on either side of the trunk. from there you can grind the trunk, add fiberglass and epoxy to re-enforce the areas that have weaken over the last 3 1/2 decades of abuse.  Afterwards Install inpection ports in the new holes you created. This process is very awkward and difficult. Again, consider aquiring a 'new to you' hull.

Good Luck,

Joel

   Or fill between the hulls with water and see where it leaks out.

Of course, you will then have to make sure it's dry before repairs are made as described above.

There must be a Laser forum to find more information. Even sailnetforum might help

ggray- thanks for the advice.  Alas- for other reasons and at the last minute I just sold the boat!  Maybe you comments will be helpful to other folks.