Adding Y-valve/macerator

[EpicAdventure]

A lot of the boats we are looking at purchasing don't have Y-valves or macerators installed. I could foresee wanting to have a Y-valve of some sort to avoid having to pay for pump-outs and be able to use when we are outside of the no discharge zones.

If you add one, do you typically have to add an additional through hull? Or can you plumb it to an existing through hull? (I could see maybe plumbing it to a sink drain or something -- but would probably want to be very careful with how the values are set up. I could easily see you pumping that stinky effluent into the sink!! )

For the very occasional uses, what about something that would attach directly to the pump-out port on deck that you could attach to and hand pump or something?

[scottyt]

yes you should have it going to its own thru hull. it will also be a large one unless you put in the grinder

edit you could also put the y valve so the toliet goes over board instead of the tank, then you have no tank to pump out as it goes straight out when you want it to

[SteveInMD]

Combining it with the sink drain is a bad idea. It needs it's own thru hull.

[CaptainForce]

I think the simplest plumbing to achieve your needs would be an obligate hose from the head to the holding tank and a T at the effluent from the tank that leads to a macerator followed by a through hull with a lockable valve and the deck pump out at the other route from the T fittings. A vacuum draw to the macderator is achieved with the pump out deck plate closed and the draw at the deck is achieved with the through hull closed. I used this simple plumbing for more than twenty years with no failures. Compliance is gained without a Y-valve, but you must lock or remove the handle to your through-hull. Take care and joy, Aythya crew

[sailingdog]

My recommendation would be to plumb the output of the head directly into the holding tank. Then install a diverter valve into the holding tank pumpout line. You can probably use the diverter valve that was previously in the head's output line that allowed you to either go to the holding tank or dump directly overboard. Have one side go to the deck pumpout fitting. Have the other side go to a macerator pump or manual diaphragm pump and then to the seacock that was previously attached to the head output.

This doesn't really lose you any capability, since any place you could have dumped the head overboard, you can now just dump the holding tank overboard. In fact, this simplifies your plumbing and gives you the additional capability to dump the holding tank, which you lacked previously.

Some people do this type of installation without a diverter valve, using a "Y" instead. I recommend not doing that. The diverter valve acts as a safety to protect the macerator or diaphragm pump from accidentally having seawater drawn back through it via the pumpout should you accidentally leave the seacock open. Forcing water through either type of pump in reverse may damage them.

[Omatako]

If you're planning on doing any long distance sailing or even spending time away from full-on civilisation, there are going to be few pump-outs and the ability to pump the head directly to the sea is a considerable benefit.

Since you will have to put a new skin fitting in anyway you may as well prepare the boat to pump directly to the sea as well as to the tank. In this setup you can get the best of both for very little extra cost. Here's what I did on my boat (I hope it makes sense because it's not easy to explain):

• Take the outlet from the head to a Y valve.
• Take one out leg of the Y valve to the top of the tank
• Take the other leg down to the skin fitting

This will give you the choice to pump to tank or to sea. On the tank:

• Take the outlet pipe to a Y piece (note, not a valve)
• Take one leg of the Y piece up to the deck outlet for the dockside pump-out.
• Take a line from the other Y-piece leg to the inlet of the macerator.
• Take the outlet from the macerator to one leg of another Y piece. Make this connection as near to the skin fitting as is practical
• Connect the line that goes down to the skin fitting from the Y valve (originally from the head) to the other leg of the lower Y piece.
• Connect the outlet of the lower Y piece to the skin fitting.

Now you can suck the contents from the top and the macerator will prepare the black water for ejection by finely cutting it up as it pumps. Contrary to what some folks might tell you, the macerator will not feed back up to the head because the joker valve in the head prevents this. If for some bizarre reason it does, just make sure the Y valve is set the other way.

This works a treat on my boat and it is set up exactly like this.

[EpicAdventure]

Omatako,

I think what you are describing is shown in the "before or after" picture on this link:
Installing a Head by Don Casey

Although instead of the y-valve after the tank, you are just using a y-connector.

[mitiempo]

Wow, that sure is a lot of hoses and connections. Any of which may leak and they all need periodic maintenance. Dog's idea is just about the best I've seen, straight from head to holding tank and out to deck or macerator/through hull. Much simpler and you eliminate at least 3 connections that could be a problem.
I think most boats have a through hull from the factory. Maybe the original poster is not able to locate it?

[chef2sail]

We did this project last year>

Head goes direct into the holding tank. Valve at the bottom of the holding tank output so you can keep the tank contents only in the tankl and not in the hoses until you are ready to pump out or macerate out. This additional va;ve will save you hioses from sitting and filling up with effluent till time to evacuate. It is usually the hoses which start to smell first. Hose from Valve to Y valve. One side leading to deck pump out. Other side leading to macerator and then to thru hull. This Marlon Y Valve has a place for padlock for CG inspection.

Dave

[JimsCAL]

Originally Posted by CaptainForce

I think the simplest plumbing to achieve your needs would be an obligate hose from the head to the holding tank and a T at the effluent from the tank that leads to a macerator followed by a through hull with a lockable valve and the deck pump out at the other route from the T fittings. A vacuum draw to the macderator is achieved with the pump out deck plate closed and the draw at the deck is achieved with the through hull closed. I used this simple plumbing for more than twenty years with no failures. Compliance is gained without a Y-valve, but you must lock or remove the handle to your through-hull. Take care and joy, Aythya crew

My previous boat had this setup and it worked well. No chance of accidently putting effluent overboard and simple. Current "new" boat has multiple Y-valves to permit head to discharge to tank or overboard, and empty tank with pump overboard or via pumpout connection. I think I will simplify it as outlined.