I bought my replacement holding tank from
www.marinesan.comIt is an odd shaped tank.
The model number was 500 which fits almost exactly. I put all my fittings on top of the tank because the old tank had the fittings on the stern end and the seals failed leaking nasties into the boat.
The pumpout nozzle I put on the aft end of the tank. The inlet nozzle went to the middle of the tank and the 1/2" vent and water flush nozzles went to the forward end.
While I was replacing the tank, I replumbed all the hoses. The head discharge went straight to the inlet nozzle. The vent and wash out nozzles stayed separate. The pumpout nozzle went to a "T" fiiting. One outlet from the "T" went to the pumpout nozzle for normal pumpouts. The other connection goes to a manual macerator diaphragm pump and then to the overboard discharge. The overboard seacock is normally sealed closed but we have learned to stroke the valve once a month to keep it moving. Sealife builds up on the outside.
Attachment:
File comment: From top of hanging locker, looking down. P1000414.JPG [ 152 KB | Viewed 0 times ] Attachment:
File comment: Hoses from tank in front. Head discharge against hull. P1000413.JPG [ 142.5 KB | Viewed 0 times ] The mistake I made with this system was I did not run the head discharge hose straight up above the tank height. So when the joker and base valves fail, a bunch of liquid runs back into the head. But otherwise, the new piping works great. Plus when the Coast Guard pulls up alongside, you don't have to worry about whether or not your head valve is in fact closed and sealed.
There is a story there but I am not sure if the statute of limitations has run out yet.