Is there a customary size for a head sink through hull?

Rachel · Post by **Rachel** » Mon Apr 09, 2007 8:53 pm

I'm considering adding a through-hull for a future "head" sink drain and I'm wondering if there is a customary or preferred size for this.

I could conceivably run a drain hose to the galley sink drain, but it seems like a long run, and I may eliminate the galley sink drain through-hull anyway (if I put in a deeper sink I'd have to close the seacock in anything but perfectly flat conditions).

Or is a long drain hose run preferable to one more hole in the boat? Even if I eliminate the galley sink through-hull, there are still the cockpit scuppers, which I think I've decided to keep below the waterline (I can't tell for sure if they would work above the waterline). The proposed head sink would be in the usual hanging locker space, so it would be about 10' or so back to the cockpit scuppers (or about 7' to the galley sink through hull).

Back to my original question though, I'm wondering what size through-hull to install for a head sink if I do put in a dedicated drain for that.

Thanks,

Rachel

Post by **Tim** » Tue Apr 10, 2007 6:16 am

A 3/4" fitting is adequate for a small head sink.

As nice as it is to minimize the number of through hulls in a boat, that doesn't mean that avoiding one should be the choice if one is truly needed. A carefully installed through hull is just as safe as an unmarred hull, in my opinion, so if you need a new one, put it in. If you don't need it, don't.

My feeling is that you wouldn't be very happy trying to lead the drain hose way back to the galley from the head. If you think you might install a powered sump pump chamber, however, such as for a deep galley sink, I would be inclined to forgo the head sink through hull and run the drain line, when you actually install it, to the new sump.

bcooke · Post by **bcooke** » Tue Apr 10, 2007 11:12 am

Or install the seacock for the head sink and if you decide you don't want it later simply remove it and fill the hole. A simple project for someone with your recent experience.

And with the amount and frequency of water usage at the head sink you could probably put a quart sized bucket under the drain and just toss it over the side once in a while; thereby foregoing the seacock.

Or wait until you have a head sink, use the bucket trick temporarily and then some year when you haul out for a good scrubbing and repainting, toss in a seacock which will only take an hour or so.

It doesn't have to be done all at once. Like the Energizer Bunny it just keeps on going and going and going and going and going...

-Britton

Hirilondë · Post by **Hirilondë** » Tue Apr 10, 2007 7:10 pm

Here is my head sink:

It is a $10.00 stainless mixing bowl from the hardware store. It sits in the counter supported by the rim and when done it comes out for dumping in the galley sink. The through hull was easy :>)

Quetzalsailor · Post by **Quetzalsailor** » Wed Apr 11, 2007 8:41 am

That's a gorgeous piece of work, David!

Rachel · Post by **Rachel** » Wed Apr 11, 2007 1:07 pm

That does look really nice. I have a friend who used a bowl like that for a (draining) sink on a small Bolger boat. He found that he had to take it back out and "dent" the bottom a bit so it would drain properly. Sure beats the price of some of the boat-specific sinks though.

Rachel

James384 · Post by **James384** » Thu Apr 12, 2007 1:00 pm

Rachel

Did you consider installing a thru-hull fitting a few inches above the waterline for the drain? Then attach a shut-off valve either threaded onto it, or if you use a barbed hose fitting, then put the shut-off valve anywhere between it and the sink drain. Parts are cheap, maintenence easy and no danger of sinking the boat, except when heeled. Keep in mind any sink mounted low and much outboard of the centerline means a chance of splashing water when heeled in a wild sea, so have the shut-off valve handy to reach. Assuming you need a sink three steps from the galley sink at all...

James
#384 Atom

Ceasar Choppy · Post by **Ceasar Choppy** » Thu Apr 12, 2007 1:27 pm

James384 wrote:Rachel

Did you consider installing a thru-hull fitting a few inches above the waterline for the drain? Then attach a shut-off valve either threaded onto it, or if you use a barbed hose fitting, then put the shut-off valve anywhere between it and the sink drain. Parts are cheap, maintenence easy and no danger of sinking the boat, except when heeled. Keep in mind any sink mounted low and much outboard of the centerline means a chance of splashing water when heeled in a wild sea, so have the shut-off valve handy to reach. Assuming you need a sink three steps from the galley sink at all...

James
#384 Atom

I did this on my P-39. On mine though, that waterline TH also serves as the exit for the shower sump and the air conditioning cooling water...

I also put a loop (just looped the hose) in the sink drain hose as a "trap" of sorts. Haven't had a problem with it.

Rachel · Post by **Rachel** » Thu Apr 12, 2007 5:35 pm

Hi James,

Thanks for that idea - that could be a good solution.

I go back and forth about whether I need (make that want) two sinks so close together. I think what I really want is a place to put my toothbrush and comb that isn't where I make food, but of course that could be accomplished with a shelf.

Another thing is that unless I keep the shallow sink currently in the galley (another decision I have yet to make), I'll have to run that drain through a sump (at least then it can exit above the waterline; I'd use a manual pump) so it won't drain directly overboard. It can be nice to have at least one straight overboard drain, and if that's the case, I might as well have a sink attached to it.

And then I have to decide whether to fill in or replace the head intake and discharge....

I told myself I'd be ordering my through-hulls and seacocks tomorrow, but I can always return one if I don't decide to use it. I'll probably order a 3/4" just in case.

Thanks all,

Rachel

Chris Campbell · Post by **Chris Campbell** » Fri Apr 13, 2007 9:09 am

On Weatherbird our head sink drains through the same through-hull as the head intake, and I've seen no problems with this arrangement. I guess you might end up with soapy water pumping into the head if you were flushing at the same time as you were draining (would that clean out the head?) but I haven't seen that, or had any difficulties with it so far. One side benefit to the arrangement is winterizing - I just close off the seacock, dump a bunch of plumbing antifreeze in the sink, and pump! No detaching of hoses to fill the head with antifreeze...