Thank you so much! I actually had to try this twice since my tube of epoxy was old and would not set up even after 30 hrs. I cleaned it off and replaced with Marine Tex grey which set up nicely in about 6 hours.
Next question: how long did this repair work for you? I am cautiously using the head now and nervous about wether the bonding will survive bouncing around in heavy seas.
Note to other SM owners: the aft head fiberglass pan has two holes in it in the vacinity of the ball valve. If any of the holding-tank plumbing leaks, the waste goes down these holes and then has be cleaned out from UNDER the shower pan (yuck!!). I used plumber's putty to seal the hole for the tube from the macerater and adhesive- backed foam to seal the cover plate for the access hole. For me, this was closing the barn door after the horse was out . . . but for some of you . . .