Head Installation

[Flying Knight]

I'm hoping maybe you guys can point me in the right direction with my head installation. I bought my boat from an estate, so I wasn't able to ask the previous owner exactly what he was doing. I pretty much have a complete system set up with a holding tank that can be pumped overboard, but the toilet itself is not installed, and the plumbing isn't fully connected either.

I took pictures that I'm attaching here of both the plumbing and the diagram the previous owner made of his plan.

What's the smaller hose connected to the through hull for?

Can anyone give me advice for adding a pump out? (e.g. where in the setup would I plumb the line and what additional hardware is needed, will I lose my ability to pump overboard when offshore?)

It looks like the previous owner got stuck at actually mounting the bowl in the head. The instructions state a backing plate needs to be installed beneath the pan, sandwiching the pan between the head and the backing plate beneath. Problem is there's no access. Is there any other safe way to mount the toilet, or will I need to cut into the pan somewhere to get access and install the backing?


Plumbing under settee


Porta-potty is temporary. I have an actual toilet to replace this.


Sketches of previous owners plans.


Sketches of previous owners plans.

[onestepcsy37]

from a first look it appears to be a 'normal' installation.

you've got one 1 1/2" hose coming out of the toilet and going to a Y valve.

you've got one 1 1/2" hose coming out of the Y valve and going to the holding tank.

you've got one 1 1/2" hose coming out of the Y valve and going to the through hull valve.

the Y valve allows you to select between pumping in to the holding tank or pumping overboard via the through hull.

to pump out the holding tank via a shoreside pumpout connection you will need a 1 1/2" hose going from the holding tank to a deck fitting.

to make the toilet work, you will also need a hose that supplies water to the toilet; my system uses a 1/2" hose connected from the toilet intake to a through hull.

sounds more complicated then it really is. that's why a drawing a diagram helps.

[Stu Jackson]

Try the WM Advisors. Their preferred layout has a flaw, yours is better, 'cuz you don't have to always go through the holding tank.

Any and all head manufacturers also have diagrams.

[Brown Sugar]

onestepcsy37 sounds like he know what he's talking about and yes, it's confusing.
I installed on my last whole system but it was easy because it was just intake, toilet, tank, pumpout.
My current boat has direct overboard from head, head to tank, from tank to overboard and from tank to pumpout with two y-valves, a shut off and the intake shutoff. I felt retarded when first looking at it and couldn't tell what end was up. When I finally figured it out I put arrows and directions on the hoses.
The only suggestion I can give is find a boat with the similar set-up and add your modifications. It is confusing but the more you look at the clearer it'll become.

[Cheechako]

No need for the Y valve, replace it with a bronze T. When you shut the thru hull seacock it does the same thing.

[Flying Knight]

I pretty much understand the system after having stared at it all afternoon. The only things that still have me confused are the pump out and actual attachment of the toilet to the pan.

I can't seem to get a straight answer on this one point - is the macerator used when pumping out or just dumping overboard? Will I need to put a second home and hose at the bottom of the holding tank for the pump out, or maybe another y valve just routed to the deck fitting?

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[dohenyboy]

Macerator is only used to evacuate the tank into the water, via the thru hull.
Pumpout goes from the bottom of the tank to the deck fitting.

[onestepcsy37]

as to attaching the toilet to the pan, i'm afraid that you'll have to figure that one out yourself. whatever you do, make it a good solid installation; i'd hate to be sitting on the throne in a seaway and have it break loose from the pan....

a macerator pump is a whole 'nother story. i don't have one, but i think if i did i would route the pipes a bit differently. try this -

1 1/2" hose from toilet directly to top of holding tank.

1 1/2" hose from bottom of holding tank to macerator pump.

1" hose from macerator pump to through hull.

in other words, everything goes to the holding tank. the holding tank can be emptied into the ocean by running the macerator pump.

now, if you also want a deck pumpout, add the following;

in the 1 1/2" hose that goes from the bottom of the holding tank to the macerator pump, put in a Y valve. you can now add a second 1 1/2" hose for the deck connection. by use of the Y valve you can either exit to the macerator pump or to the deck connection.

for deck pumpout you do not use a macerator - the pumpout machinery has all the suction it needs. the macerator is only if you want to pump out the tank without using shoreside facilities.

i have no experience in this, but i wonder if, instead of the Y valve, you can simply use a T connector. if someone has experience in this, i'd like to hear your comments.

[Cheechako]

You can just put a T in for the pump out, under the tank. Those plastic Y valves have a habit of breaking and/or sticking sometimes, so the fewer the better.

[Terra Nova]

Cheech--good post.

As for backing up the hull liner, you need to add beneath the toilet base a piece of 3/4" exterior plywood large enough to accept all the toilet's mounting fasteners and spread the load over a large area. If there isn't enough space to reach in underneath the liner, then you must devise a way to snake one in using a string running through a small hole in the liner and the backing plate, and hidden by the toilet. A small screw-eye can aid positioning the plate.

It can be helpful to add threaded inserts into the plywood so that machine screws can be used to attach the toilet--much stronger and able to be R&R'd many times. I coat the top of the backing plate with 5200 or epoxy, then draw it up with the string and install 1 or 2 small flathead sheet metal screws to hold the plate tightly against the bottom of the liner while the glue cures.

Look at and understand the systems shown here.
Selecting a Sanitation System | West Marine

If your system doesn't look exactly like one of these, it's probably wrong. So inquire.

[Flying Knight]

Thanks. That link is to head treatment info.

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[Terra Nova]

Judging from your photos, the PO didn't do you any favors. Especially cutting up the bulkhead to install the holding tank. That hose snarl likely won't interface well with the new toilet. You shouldn't see a mess like that in the head.