Removing Holding Tank

[trashpad]

I would bet on a clogged vent line when you went to pump it out. It would not take much vacuum to crack the fiberglass. The other thought was that you left it full over winter and it froze. The hard messy work is behind you now. If you can not get the correct size tank why not fiberglass this one back up? Grind back until you get to clean epoxy and lay some layers of glass.

[Cathyalan]

Vent...possible. It was a salty boat and when I checked the vent outlet at the hull, some of the "screen" holes were closed with salt/crud but I put an air hose at the tank end of the vent hose and air came out the hull outlet quite well but sh_t happens. Leaving the tank full in winter in Wisconsin is just plain stupid.

The new tank measurements are quite compliant with the T28 bow/hull and it's shape is very similar to the fiberglass original and it's even a bit bigger at 13 gallons. It's molded, no seams, 3/8 inch polyethylene. I plan to mount it with 4, fiberglassed, oak tabs attached to the hull so it can be bolted in...if it ever needs to be removed and/or I ever decide to add an off-shore dump pump to the thruhull I have easy removal.

If you have an opinion about my mounting idea, please share. You have been very helpful.

Alan