All,
I am finishing my tank installation now. Tank, hoses, deck fitting, shower seat, shower wall, and head have all been installed. I'll post some final photos.
Two things I don't have photos of: the shower seat repair detail and the tank tie-down detail. I used the same 1/4" FRP that I used to build the tank and cut in 2" wide strips to backer-block the shower seat joint. Screwed together at 4" spacing, the joint is very strong. When I first planned out the project, I feared cutting out the seat. Now that it's done, I'm not unhappy with the way it turned out. The seat HAD to come out to remove the old tank. I can hide the scars with teak molding someday, probably never. Just seal the seam with latex caulk.
Also, no picture of the tank tie down. I will use a 1" wide lashing strap with cambuckle (from Harbor Freight). Screw the strap ends to bulkheads on either side of tank and ratchet it down snug.
Thanks again to all the knowledgable boat owners who post to this forum. I have more projects planned, thanks to your help and inspiration.
Cheers,
Doug