Sink Drain

[wingover]

Hi,

Our new boat has the galley sink at midship port side. The sink's bottom is around 16" above the waterline. The curent setup drain to a Macerator pump and out of the pump to a vented loop about 20" above the sink level. We really hate this setup as you have to drain the sink every few min with the pump when washing dishes. I am worried about connecting the drain stright to the thru-hull to avoid flooding the boat when sailing on that side.

1. how can I know if the sink will be underwater line when sailing?
2. is there another setup that is safe without using any sort of pump?

I have attached a picture I found on the web, showing a vented loop. will this work?

[GordMay]

Use a halyard to haul the boat over to maximum heel, whilst at dock. The sink will flood, or not.
A "vent" helps a fixture drain without "burping", by allowing air in behind the water plug. Nice, but not required on a boat.

[Jentine]

Remove the pump, install shut-off valve, remove the vented loop, go sailing.

[Solitude]

Gords right. Test and see.

I dont have a vented loop but my sink drain is 2" above the waterline. Do you currently have a through hull below the waterline or are you drilling one. If you are drilling a new one I would try to keep it above the waterline. It would give you peace of mind leaving it at the slip, or at least one less worry.

However heeling the boat and having my sink drain 2" above still means that water can get in. I tend to shut mine while cruising.

[daddle]

Yeah, skip the vent. Hauling the boat over on a halyard is a good one. But easier is to locate the waterline inside the boat then run a string from that height at the center of the boat to the shearline (toerail) inside the cabin. Whatever is below the string will likely be underwater at some point. This is not strictly accurate from a naval engineering standpoint but it should be close enough.

To find the waterline inside the boat just disconnect the sink drain hose at the sink and with the seacock open slowly lower the hose until seawater comes out. Mark that point on a bulkhead, it's often useful.

[wingover]

Thanks for all the replys. I am trying to avoide having to shut off the ball valve if I remove the pump as you might forget it one day.

My thru hull is about 6" under the waterline.

I wil try to mark the waterline to see if the sink goes under.

[Liam Wald]

Someone suggested the drain be located "above the waterline".

To me that sounds like a really bad idea. A sink drain is basically a "graywater sewer".
Having the drain above the waterline would create a a pretty disgusting streak of crud down the hull!

Ever do any plumbing and see the inside of a well used sink drain?

[Sailmonkey]

Sure, above the waterline. there are lot a production boats that have drains, even head discharge above the waterline. I put the head discharge in the bootstripe on my previous boat, never had any unsightly streaking. We're not talking way above the waterline, just barely.........but this still doesn't solve your heeled waterline issue.
On our boat now, when sailing on stbd the sink has about 2 inches of water in it, no big deal as the sink is about 14" deep.

[Solitude]

Yupp

There's alot of boats wit the drain just above the water line. Look around in your marina.

[roverhi]

A sink bottom that is close to the waterline but not bleow it can be a problem under sail. Our old boat had a near center located sink that was above the water line. Workedokay in port but sailing on stbd tack would fill the sink and overflow onto the counter top. Would have taken a while to sink the boat but created a hell of a mess. We got one of those large thermos type lever stoppers and used it under sail. Solved the problem underway though we needed to ease up a bit to cut down the angle of heel and it worked fine. It wasn't a problem if seas were relatively flat but that was never the case out on the big pond.

The sink will drain faster with a vented loop, btw.

[wingover]

Thanks for the input. I guess I'll take the pump off and install a ball valve.