how do i install a sink (and not sink..)

[plankton]

can anyone help please..i wish to install a small wash basin in my boat's loo and hoped for advice on basic plumbing ? eg: heeling etc will water come back up the outlet ? is it advisable for the outlet when going via an existing seacock to be fitted before or after the water lock type bend ? i plan on the inlet from the fresh water tank... any suggestions greatly appreciated

 

[Blueboatman]

Waste into shower tray
Waste into loo (bit dated)
Foot pump for waste,coupled with swan neck in waste taken high up inside a locker...
Non return valve
Mount sink high enough to prevent flow back when heeled

 

[Sea Devil]

If it is an existing sea cock and the sea cock is in good working order I think you can go direct. The height of the sink waste pipe - waist height - means it is very unlikely to be below the waterline even when heeled over quite hard.

On all my boats the sink outlet has been at roughly the waterline - of course via a sea cock and the pipe has been a straight run.. I think the reason for no bends in the pipe and for the sea-cock to be just above the waterline is that otherwise the water will not flow out of the sink properly. Pretty straightforward installation.

Michael

 

[Evadne]

[ QUOTE ]
it is very unlikely to be below the waterline even when heeled over quite hard.

[/ QUOTE ]
I would beg to differ, having filled up the galley sink and drainer when I forgot to close a seacock, /forums/images/graemlins/crazy.gif but otherwise agree. If the existing seacock he is going to use exits below the waterline then it will empty, just more slowly than you're used to.

I took out such a sink, 'cos it never got used and the extra piping through the cabin was further breeding ground for algae, which needs surprisingly little light to coat a pipe, so would suggest opaque piping if possible.

 

[Toryboy1]

My heads sink floods when on stbd. tack so I have to keep the seacock closed when sailing, it's well below the water-line. I had the same problem on the galley sink until I fitted it with a pump to empty, which effectively acts as a one-way valve. I picked up one of those nice brass Whale bilge pumps in a boat jumble for a tenner, though you could use a diaphram pump. In that case, you can also have a swan-neck well above the water-line.

 

[andy_wilson]

If the sink is under the side deck it may well flood whilst heeled. If you have space to mount it nearer the centreline of the boat there will be a point when it will not.

The drain should go above the waterline if possible, for the simple reason that a drain above the waterline is better than one below it, if a seacock, pipe or clip fails.

Next time you sail fully hard pressed, make a note of your angle of heel from the compass (if it has an heel gauge) and also where the waterline comes to. On most yachts it's around the toe-rail but some sail with the side decks well under at times. Get a straight edge into the heads compartmenta nd stick it under the side deck around the heeled waterline and at the observed angle of heel.

If you can mount your sink far enough inboard so that the drain is above that marker, you will get the od splash due to hydraulicing. If the rim of the sink remains higher than that it should capture it (or most) and let it drain back inbetween. Of course if you venture out in the rough it makes good sense not to expose pipework to a hydraulic pounding, and run with the sea-cocks generally shut anyway.

If you can't mount the sink to avoid flooding when heeled you could try running the drain pipe horizontally (or with a slight downward slope) inboard from the drain before looping outboard to the drain. The 'straight edge' should show you how far inboad you need to go.

 

[plankton]

Thank you all for your help and very constructive replies. I'm so glad i asked while still in the planning stage and i will proceed based on your information/experience. Its so comforting to know you can just ask and so many people will make the effort to help. thank you all again.