Waste Tank Vent

[a64pilot]

Pauls I had contemplated that using what I call scuppers, smaller versions of what you see on older power boats to get air into and out of the engine room, think scoops, one facing forward and one aft, but I'm going to stick with the single 1" vent hose, it should be a major improvement.
I would assume what would be ideal is something like an aquarium air pump with an air stone or maybe a metal tube with holes drilled into it to bubble into the tank, but again, more work than I want to do.

[Pauls]

Yeah, and more complex. For me, eliminating motors, pumps, etc as much as possible is a plus point. Let us know how your new tank works out.

[a64pilot]

Right now as designed I have two options, I can bypass the tank by opening the seacock, or close it and pump into the tank, but only way to empty it is to pump it out via the deck fitting.
I don't relish the idea of going to the Bahamas say with a half full tank and hauling that around for months as I'm under the impression that pump outs are few and far between, and having to find a pump out is sometimes a pain, when I know I will be offshore soon.
Plus should the macerator pump break as it will eventually I am left with the stock set up at that point. It is complicating things, but the fall back is to stock configuration, I can live with that.

I'm not doing the air injection thing, as you say too complex and something else to maintain and eat electrons

[Tricolor]

Vetus has tank vents up to 38mm

[Badsanta]

If you can empty your tank via the macerator and a thru hull. Add to or replace the macerator with a whale pump. My boat everything goes to tank. Then y valve to deck or thru hull. Use an inline whale pump to empty tank at sea and when in harbor no mistakes. Works great.

[a64pilot]

I had thought initially to use a diaphragm pump, but they are large, expensive and need a 1.5" thru hull, a Macerator is smaller, less expensive and only need a 1" thru hull.
I hope to not use the pump all that often, where I am now its just too easy to pump out and once we go, I expect to direct discharge the majority of the time, the pump is to keep from having a partially filled tank for extended periods of time, I assume over time it would sludge up and you would have build up in the tank that would be hard to get out.
I'm having a inspection cover installed in the new tank, just hope to never have to use it

[Frankly]

This will be a little drift, but I redid the waste system on Cbreeze 11 years back and it has worked out really well. I moved the vent closer to the tank and plumbed it with sch 40 PVC. Used a std bronze mushroom for the vent fitting which has been turned black by the gases.

The head now discharges directly into the top of tank. Pump out is via a Y valve (overboard macerator, or deck pump out). Most of the connections are PVC with some short lengths of hose at difficult transitions.

By pumping directly into the tank you are not pumping against a couple of feet of head pressure (head works easier), and that 2" overboard valve is normally closed.

No sludge build up in the tank, flush it out with water and use a water softener, look into the inspection port every winter to see if the aluminum has bit the dust. Would not want to sleep in there but not all that foul.

For the tank full and the macerator just bit the dust, I carry a diaphragm pump on a board , on board with the interface fittings. Couple of spare macerators pumps.

No odor, no problems, new joker valve every couple of years. 25 YO Raritan PH. Did install a rebuild kit 11 years back.