Holding Tanks

I'll relate a different regimen. A Porta-Pottie was used to replace the original Raritan toilet, and I got rid of it. I was not wowed by the concept of that stuff floating under everything, and the problem getting it out (there was no hosing to the deck). Worse, I feared a spill in high seas.

My Ariel has an outboard, so if yours does also, this might be an alternative. I do long cruises and the holding tank is a concern. I put a 13 gallon holding tank under the cockpit floor, essentially pressed up against the rudder post, sandwiched between the two cockpit lasarette peg boards and mounted so it was level.

For a toilet I used a macerator toilet for these reasons: Flushing takes less water; the smaller 1" hose is easier to get through from the front to the rear of the boat (it bends); and the space is essentially otherwise unusable .

The breather tube goes into the engine well - as high up as you can get it, and on the side opposite side holding tank breather fitting. The pump out is aft, just forward of the end of the lifeline on the port side. The input is the original Ariel input. The original output has been capped.

I placed an anti-siphon fitting just ahead of the tank, between the tank and the toilet, and also one on the input line. This latter is mandatory (and the former one may be also)

I was concerned about the weight of a full tank (13X 8#/gal = ca. 104 lbs when full) being that far aft, but have not had any real problem. In fact, when the hull is only slightly noticeable rocking backward, that is my guage that a pump out station should be the next destination.