I have been fighting a slight holding tank leak on Rauzer II #448 for a couple seasons and have only made it worse. I now need to either have it repaired or replace it. The problem area is at the bottom of the pump out fitting. The motion of the tank flexing and the hose bouncing has either ruined the threads on the pump out fitting or there is a crack at the bottom of the fitting.

Has anyone replaced their holding tank? It looks like it could be removed from the mounting and lifted out, into the v-birth, but I don't see how it could then be removed from the boat. The other option would be to pull it into the v-birth and then have the bad fitting/area cut out and new parts plastic-welded back in.

Any experience out there with this kind of job?

Had similar problem. I think the leak was through the threads between the main pump out hose connector and the tank.

In addition I inspected and replaced the small ventilator hose which was kinked at the top near the hull/deck where it exits. I added an L connector to keep it from kinking. Thought maybe tank pressure was building up in summer heat contributing to leak.

Replaced the main pump out hose and sealed the threaded connector fitting to tank with 3M 5200.

The tank itself is very thick-walled so I doubted that it was cracked anywhere at the bottom where I could not see.

Cannot attest to this fix as it was done this season but so far so good...

I didn't have to replace any cracked fittings or the tank, but have done a complete hose replacement. Make sure you use a heat gun to soften the hose when removing and putting on new hose, or you will need lots of force to go over the plastic fittings. This force could easily contribute to the cracking problems you have. If the 5200 solution mentioned above works, I say do it.

The discharge of the tank on Rhapsody is attached to a hose about 5" long, connected to a Y-Valve that is bolted to a plywood board. The board is cut as a trapezoid so it sits flat, on both sides of the hull to support the Y-Valve and the macerator pump. If you have flexing on the discharge at the bottom of the tank, consider adding the plywood support and clamp the hose to it to prevent movement.

I should add that the threaded hose connector on mine was NOT cracked after inspection and in good shape, therefore my feeling was that the 5200 generously applied to the threads would create a good seal. (There is about an inch and a half of thread in the tank so a lot of threaded surface was covered with 5200 -- a very thick tank.)

and yes, I had to use a propane torch to heat the new hose (carefully!) to make it pliable enough to slip on the connector. A couple of hose clamps and that was it.

I pulled the tank today and found that it will just fit between the mast, door and woodwork, so I am taking it to a place to have the bad thread fitting cut out and a new one welded in. I actually tried the 5200 trick, but the threads were too worn from the tank flexing and the hose bouncing.