using one of the sensor hole for the new head's water input

JoeWhite · Jul 10, 2019

The head will require holding tank and pump out hose. I do not think there is enough room. I use fresh water to flush as sea water stinks due to dying bacteria.

Peggie Hall HeadMistress · Jul 10, 2019

JoeWhite said:
The head will require holding tank and pump out hose. I do not think there is enough room.

Nor should any toilet designed to use sea water ever be connected to the boat's fresh water plumbing, and every toilet mfr specifically warns against it because of the risk of contaminating the fresh water supply with sea water and/or bacteria fro the bowl. But there's enough room for this:
On any boat much smaller than about 28', a self-contained system—an "MSD" portapotty-- makes a lot of sense. The "MSD" designation in the model name/number means it has fittings for a pumpout line and vent line, and is designed to be permanently installed (actually just sturdier brackets than portables, so you could still take it off the boat if you absolutely have to), which means that although it's still called a PORTApotty, you don't have to carry anything off the boat to empty it.
A 5-6 gallon model holds 50-60 flushes...you'd need at least a 30 gal tank to hold that many from a manual marine toilet. No plumbing needed except a vent line and pumpout hose--so no new holes in the boat...and -0- maintenance needed except for rinsing out the tank--which you can do with a bucket while it's being pumped out. Total cost including the pumpout hose and vent line is about $200--a fraction of what you'd spend for toilet, tank and all the related plumbing needed. And the best part is, you have all the advantages of a toilet and holding tank without giving up a single square foot of storage space.
Check out the Thetford 550P MSD and the Dometic/SeaLand 975MSD Sanipottie . Thetford has discontinued the 550PMSD, but it’s still available from most retailers…the Dometic 975MSD is still in production. They’re comparable, and not much can go wrong with either one, so if you like the Thetford find out if sbo.com still carries it before shopping for it elsewhere. Sbo.com does have the Dometic 975MSD.

--Peggie

Peggie Hall HeadMistress · Jul 10, 2019

JoeWhite said:
I use fresh water to flush as sea water stinks due to dying bacteria.

I hope you haven't connected your toilet intake line to the boat's fresh water plumbing because that's a major no-no. However, there's another SAFE solution that's very easy and inexpensive:
Reroute the toilet intake line to tee it into the head sink drain line...the tee needs to be below the waterline, as close to the seacock as possible ...This will allow you to flush normally with sea water.
After you’ve closed the sink drain seacock in preparation to close up the boat (you do close all seacocks before leaving the boat to sit??), fill the sink with clean fresh water and flush the toilet. Because the seacock is closed, the toilet will draw the water out of the sink, rinsing the sea water out of the entire system—intake line, pump, channel in the rim of the bowl and the discharge line,(Water poured into the bowl only rinses out the toilet discharge line). If your toilet is electric, be careful not to let it run dry…doing so can burn out the intake impeller. Or you can keep the sink drain seacock closed except when it's needed to drain the sink and flush with fresh water down the sink all the time...your choice.
It may also be necessary to keep the sink plugged except when in use, with a rubber sink plug or by installing a conveniently located shut-off valve in the drain hose. Otherwise the toilet may pull air through the sink when you try to flush, preventing the pump from priming...or on some boats, pressure of the water against an open thru-hull when underway on that tack can turn the sink into a fountain.

--Peggie

Peggie Hall HeadMistress · Jul 10, 2019

I'm sure you'll hear from a whole bunch of smaller boat owners here who've installed one and love it.
But it can also be an excellent "stopgap" solution on a much bigger boat. I'd been helping someone (not on sbo.com) who's also on the Great Lakes spec out a whole new sanitation system on a new-to-them 42' sailboat...not quite a project boat, but still needs equipment that's gonna eat up enough of his budget that he finally had to accept the need ro delay buying the pricy macerating electric "throne" he really wants for a couple of years. We discussed several compromises, all of which were also gonna require spending money for some kind of toilet, tank and all the hoses...until I said, "This is really off the wall for a boat this size, but it'll get you out of the slip and onto the water with toilet facilities for next-to-no money--an 'MSD' portapotty. You can replace it with the Raritan Marine Elegance you really want after you've fixed what HAS to be fixed and had some economic recovery. " After very little discussion, they went for it! Installed it about 2 months ago and couldn't be happier.
--Peggie

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Crazy Dave Condon · Jul 15, 2019

Peggie Hall is also a good source and suggest listening to her as well @kco

JoeWhite · Jul 16, 2019

Peggie, I flush the head with the removable sink spout. Or I pump the used sink water into the head then to holding tank.

Peggie Hall HeadMistress · Jul 16, 2019

JoeWhite said:
Peggie, I flush the head with the removable sink spout. Or I pump the used sink water into the head then to holding tank.

I assume you mean you just add water to the bowl using the shower head. That's fine if you only want to flush out the toilet discharge hose...'cuz flushing the toilet only sends bowl contents--whether waste or clean water--out the bottom of the pump. It doesn't recirculated the flush--nor would you want it to!-- through the intake line, pump and channel in the rim of the bowl,, which is where the stagnant sea water is. That's the beauty of teeing the intake line into the head sink drain line...the water in the sink rinses out the entire system.
As for flushing with used sink water (gray water)...bad idea, 'cuz it's full of bacteria, soap scum, body oils, dirt, toothpaste etc that are full of bacteria and also can be damaging to the rubber parts in the toilet.
--Peggie