Galley sink waste outlet

[jon]

My galley sink base at the outlet is to be 180mm above the water line, and 500mm from the centre line in the heavy displacement sailing boat I am fitting out.
The max angle of heel before sea water enters the bowl is therefore calculated at best to be 20 degrees.
It seems to me I have three options with the waste outlet:
1) Outlet above water line. (Advantage no hole and seacock below waterline)
2) Outlet via seacock below water line. (Advantage seacock can be turned off in rough weather to prevent entry of sea water)
3) Pumped via loop to outlet well above water line. (Best? but expensive and more complicated)
I would appreciate any comments to my plumbing dilemma.


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[poter]

Another way would be to put a non return valve in the line, available at most good plumbing shops. BSS, Plumbcenter, etc.
option 3: pumping. no don't do that just one more thing to go wrong & service.
poter

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by poter on 21/02/2004 14:03 (server time).</FONT></P>

 

[Anchorite]

Another option (I think from Larry Pardey) is a 2-way valve that can either empty overboard or into the bilge (which is then pumped out with the bilge pump). This is fine if you have a proper sump and not the AWB slosh-from-side-to-side type arrangement.
If using a non-return valve put a fairly fine filter over the drainhole: however, I don't think you will find a NRV which will work on a 180 mm head.

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[jon]

Thanks, I have not installed the main bilge pump yet, how about siting it in the galley with a diverter valve for bilge or sink?
I agree about the non return valve option probably not working, I do not like the idea of the sink water going into the bilges which the above would avoid.

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[muchy_]

"Good plumbing shops, BSS and Plumbcentre"????????? ;o)
I work in a plumbers merchants and those NRV won't work very well if at all in that sort of application because they are spring loaded and need a bit of pressure to open them. Ok on dishwasher or washing machine.
The best option sounds like dropping it into the bilge to be pumped out but you would have to watch the food particules and give the bilge a good clean occasionally as it may start to smell in the summer.

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[sailorman]

the nrv will block
let dirty dish water into the bilge????????????????????????
either fit a pump to pump-out above the wl it will also act as a nrv, or better still out through skin-fitting & seacock below the wl.


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[poter]

What are you lot talking about?????
Spring loaded NRV! of course it wont work but you can get swing check valves (ok aplologies I was trying not to be too technical) in brass up to 2" also mcalpine used to make a pvc nonreturn valve, and if all else fails just put in a pvc 1/4 turn full bore stop valve, nice & easy.
There is no way I would put waste water into the bilge...yuk... if there is water already in the bilge it will be cold, then any grease will solidify and be like rock & bang goes your bilge pump

poter



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[HeadMistress]

Don't even THINK of draining your galley sink into the bilge! A wet bilge is already a dark stagnant swamp...the last thing you want to do is add more organic material--food bits and grease, along with dirty dishwater--to it to decay and stink.

A thru-hull above waterline on a sailboat is only viable if the sink will never be in use while you're heeled to the other side. If you put a loop in it, the sink won't drain completely via gravity...there'll always be water standing in the drain between the sink and the top of the loop. The drain would also be likely to clog due to build up of "stuff" sitting in it.

A check valve is also likely to cause more problems than it solves due to grease etc that typically goes down a galley sink...another potential for clogging.

So IMO, the only trouble free solution is a drain to a below-waterline thru-hull and seacock.

<hr width=100% size=1>Peggie Hall
Specializing in marine sanitation since 1987

 

[sailorman]

"CLACK" valve i assume u mean

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[poter]

>A check valve is also likely to cause more problems than it solves due to grease etc that typically goes down a galley sink...another potential for clogging.<
Hmmm....not especially...I wont argue the point too hard, but the waste pipe are usually quite small typically 1" and hopefully the waste water will be more or less full bore & hopefully hot, with any solids held in suspension. But you are right in that any valve in the line does have the potential to cause a blockage. I always advise that ANY valve is in a position to be easily serviced and is used frequently to stop it from freezing


poter.


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[jon]

Thanks Miss for that! I would'nt think of draining the sink into the bilge!
With only 20 degrees of heel before sea water would flow into the sink your choice of the below W.L. outlet and seacock is fine as long as the seacock is closed on the adverse tack in rough conditions. If only water would not find its own level!

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[HeadMistress]

Potor, hot water actually causes more problems in drains than cold..'cuz it keeps grease and oil in suspension to coat the pipe and build up. Icy water, otoh, congeals it so it'll pass on through as little blobs.

I don't know if sink garbage disposers are used in the UK, but they're common here in the US...it's recommended to put ice down them weekly to "degrease" them.

<hr width=100% size=1>Peggie Hall
Specializing in marine sanitation since 1987

 

[sailorman]

if u put a hand pump in the waste u dont need to close seacock.
its standard on contessa 32s due to same prob.

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[muchy_]

Swing valves are ok but they have a very loose action and will swing open when the boat heels and let water past.
Go the seacock route, it sounds the best way. Putting that water into the bilge would create a lot of work to keep it clean.

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[ccscott49]

Above waterline, nasty streak down side of boat! Below waterline with seacock! only way IMHO

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[Mirelle]

That has worked well for me for 10 years now

1.5" sink waste to Whale diverter valve; other inlet branch of valve runs from a strum box in the bilge sump. Outlet of diverter valve goes to diaphragm pump, thence via a loop under the deckhead and a nonreturn valve to a seacock in the topsides. If you leave the seacock 1/4" proud of the side, outboard, you don't get a drip staining the topsides.

Advantages - safety, nothing below w/l, it never blocks, and the fact that the manual bilge pump is in regular use means you can be sure of it. You need to figure out the pipe runs to get the bilge pump and two way valve in conveninent places but its not hard to achieve.

<hr width=100% size=1>Que scais-je?

 

[DMGibson]

Can you take the waste outlet to the other side of the boat?

By that I mean that if the sink is offset 500 mm to port for example, you put the outlet on the starboard side?

That gives you a fighting chance of always being able to drain the sink on either tack.

I would also suggest a seacock on every outlet through the hull, even ones (usually) above the waterline, just in case you get a lot of water in the hull.

There was a case of a motor yacht which sank in a marina berth because of a small leak in the stern gland which let in enough water to submerge the sink outlet which had no stopcock, turning a drip into a flood. Many thousands of pounds worth of damage for the sake of a stopcock.

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[ccscott49]

If you have to code your boat, all through hulls must have a seacock. Even my nain engine exhausts have seacocks!

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[MainlySteam]

I suspect that for many boats, my own included, if you calculate it as you have done, the basins would seem as if they would flood.

You will likely find, however, that as the centre of buoyancy moves to leeward as the boat heels, the basin base will remain above the waterline. I would be inclined to try it and see. You have done the trigonometry as if the centre of buoyancy remains on the centreline of the boat, it, of course, does not. The heeling boat revolves around the current centre of buoyancy, not about the boat's centreline.

John

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[jon]

Re: That has worked well for me for 10 years now

Thanks for that, your recommendations are pretty much what I had decided on after reading all the response and sitting in the boat planning pipe runs!
I would use a Jabsco diverter, they are bulkier but have swivelling angled connections making installation easier, and are easily serviced (I already have 3 in the heads for the holding tank/anchor chain locker pumping!). I am interested that you suggest a non return valve at the outlet, a possible blockage/ malfunction, is it needed? What about a siphon breaker instead, or is that OTT.
What height would you position the outlet above the water line? They look and are angled better lower down.


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