Head sink drainage

[Luders33]

How could I design drainage for my head sink besides using a sump and pump? if i run a drain line back to the same thruhull fitting as my galley sink it will have a valley that will probably trap water. would that cause odor? What about using my head pump (i have a manual lavac head) to pump out the sink drain. i guess it might be inconvienient if the sink fills up quickly because there is no reservior. i dont know i would connect to the head lines without some possible coomplications anyhow. I just dont have much room under the cabin soul for a sump unit.

thanks
Bret

[senormechanico]

How about putting in a thruhull for the sink? First of all though, make sure the sink is above the heeled waterline on both tacks.

Steve B.

Bret,

Every land based sink has a water trap in the drain that is there to ensure that sewer oders do NOT come back up the drain, so the low spot you would have would not be a problem for that reason. This arrangement would only work if the head sink stayed above the waterline all the time.

In many older cruising boats with compact heads the sink drained directly into the toilet and was pumped out from there, that would not be a solution unique to you.

If you do end up with a sump&pump arrangement, the sump can be as small as possible and still fit a level switch in.

Bill

[Luders33]

good point about the waterline. i believe the sink drain is going to be under the waterline when heeled over. hmm. i wanted to avoid using a head sump box because of limited space under the floor but if that is the only way then where would i have it pump out? through the same through hull as the bilge pumps? or is that bad?. my bilge pump through hull is in the stern above the waterline.

[Pblais]

Galley sinks tend to accumulate more trash than a head sink. You really want as short a run as possible else it will clog up a lot. The problem with a valley is that it will settle out anything you put down the sink and eventually clog up at that low point. You can ask the crew not to put stuff down the sink - but they will.

I would not tie to the head at all as I think that presents a lot of hassles too. You don't have to drain the sink below the water line either. In that case a through hull just above the water line is just fine (mine is) if it can be real short.

The sump with a small bilge pump isn't bad. At least you can put a screen on it like they do for a shower sump kit. Perhaps tie to the shower sump if that is close or combine them both. Just locate it some place you can easily clean it. They can get pretty bad if let go for a year or so.

[sildene]

Excellent post, Paul.

I thought I may mention my super simple/compact sink outlet - sink outlet is simply T-ed to the toilet intake, just above the seacock. No pump, but no low points either.


This was done by the PO and when I first saw this, I thought "what has he done!". But then, I used it for a while and no issues have arisen.
I first thought I'd have to keep the bung in the sink outlet when pumping the toilet to avoid sucking in air, but, strangely, it seems because the T-point is below the waterline it doesn't happen.

A side effect is that the sink outlet is now an anti-siphon device on the toilet intake (provided the sink is only bunged when in use).

Martin

[Pblais]

I thought I may mention my super simple/compact sink outlet - sink outlet is simply T-ed to the toilet intake, just above the seacock. No pump, but no low points either.

My last boat is set up that way. You can pour anti freeze in the head sink and pump it out the head to winterize if you close the through hull. It also was shared with the salt water washdown pump, so you could winterize that line using the salt water pump until it came out pink.

Sharing with the three things worked to make the run short and you just don't use any of those three things at the same time.

I fixed the duplicate posts in the thread.