Slow Galley Sink Drain

[nhschneider]

This may be one of the most boring posts but perhaps someone has had a similar problem and found a solution they'd be willing to share.

It takes a full two minutes to drain a quart of liquid out of our galley sink. All the other sinks on the boat drain very quickly. The drain is connected to a 3/4" hose that has a very short and direct route to the seacock - there are no kinks in the hose. The sink is at least two feet above the water line. Out of frustration, I replaced the hose and fittings - no difference. While the hose was disconnected from the seacock, I opened it. A massive geyser of sea water shot out, confirming my suspicion that the through-hull and seacock are clear.

It's kind of embarrassing to be stymied by something that appears so simple.

Fair winds and calm seas.

[Ex-Calif]

Do the other sinks drain through the same through hull?

Have you poured water through the sink with the hose removed to see if the sink drain as a problem?

Has it always drained slowly?

[GeoPowers]

Originally Posted by nhschneider

While the hose was disconnected from the seacock, I opened it. A massive geyser of sea water shot out, confirming my suspicion that the through-hull and seacock are clear.

Haha, had a good visual on this. Of course, next time we'll need a video.

Anyway, is it a one-basin or two-basin sink? Perhaps if it is a one-drain sink and you are trying to drain a whole sink full of water an air pocket may be preventing good flow?

[nhschneider]

Each of the other sinks has it's own through-hull and seacock. With the hose disconnected from the sink, I can see through the hose fitting and there's no obstruction. I haven't tried pouring water through it as it would be the same as pouring water through a 3/4" pipe ell that you were holding in your hand - you'd just get your feet wet. The funny thing is that for years the sink drained normally and I have no idea what could have changed.

[Ex-Calif]

Originally Posted by nhschneider

I haven't tried pouring water through it as it would be the same as pouring water through a 3/4" pipe ell that you were holding in your hand - you'd just get your feet wet. The funny thing is that for years the sink drained normally and I have no idea what could have changed.

I had to ask even though a dumb question...

I presume after you put it back together it is still the same. i.e. when the "geyser" shot up it didn't clear an obstruction did it?

My cockpit drains below the water line. Periodically I have to shove a pressure hose into the top end to "blow" out the crustaceans.

There certainly isn't a logical explanation to your trouble...

[James S]

Is there a vent in the sink back,,,may look like an overflow....if it got some trash in it it could make a difference.

Just because the thru-hull gushed water out when opened, it doesn't mean that the opening isn't restricted...remember that the water coming through the it is under pressure.

[Nik]

You might disconnect the hose at the thru hull, then put a bucket there. Pour your quart of water in to the sink. If it drains well, your problem is lower, if not, then your problem is above.

[delmarrey]

3/4" hose? I could barely piss thru that. I think I'd put in a standard sink drain and size the thru hull up one. Otherwise your always going to have drain problems.

My thruhull is a 1-1/2" with the plastic sink plumbing. Fisheries - Product Detail

[anglooff]

I would suggest that you are probably better to dive overboard with a screwdriver and check for a small foreign object.

Regards

Alan

[Charlie]

Originally Posted by delmarrey

3/4" hose? I could barely piss thru that. I think I'd put in a standard sink drain and size the thru hull up one. Otherwise your always going to have drain problems.

My thruhull is a 1-1/2" with the plastic sink plumbing. Fisheries - Product Detail

+1 for Del's post. 1 1/4 to 1 1/2 are the proper size for a sink drain. If your thru hull is 3/4 there isn't much you can do about it.The only thing that I can think of is some kind of air lock but have no idea where it would come from. Is it a single or a double sink?