DIY waste water (sewer) pump out system?

[Squire]

Has anyone purchased or assembled a portable pump out system for their boat?
I was just informed by our marina that the pump out system won’t be available for much longer.
I have an RV sani-station in my driveway and I’d like to rig something up to use at home. Some online searching yielded an RV system but I am curious if anyone has adapted something like it for their boat?

 

[SteveL]

I have used a standard macerator pump adapted to the pump out port deck plate. I used two ABS fittings, one screwed into the deck plate and one onto the pump. They press fit together. Make sure there are no air leaks or the pump won't prime. I poured a little mineral oil into the pump to lubricate the impeller while it primed. Normally it would not prime unless the tank was full almost up to the top of the neck. I just filled it up with a water hose.

 

[Squire]

Thanks for that. How high was your vertical draw from the tank bottom to the deck fitting?
My head has a macerator pump from the toilet to the tank already so I just need a powerful enough pump to suction out the fluid. I’m thinking once it’s primed the drop to the sewer access will provide some siphoning force to help it along.

The attached pic shows my pump-out fitting above the rub rail and the steel cover plate for the sani-station under the bow of the boat. I have to think that with the right pump and fittings it should be simple and convenient to make this work.

 

[SteveL]

That is the exact same boat that I had. I used a macerator pump because that's what I had and it was easier to adapt but you are right, once it's been through one macerator you just need a pump powerfull enough to suck it out. Key is getting it primed. Once the pump primed it would suck the tank try no problem. I just had to fill the tank up to the top of the neck so the pump only had a couple of inched to pull. I connected a regular garden house to the outlet and put it down the sewer.

 

[Squire]

Appreciate your input. I’ve got some time so I should be able to get something together before I actually need it.