Planning boat plumbing

[PaulMcC]

Hi All,
The plumbing on my boat is a mess. The toilet is on the port side with it's own seacock and works fine but I have a basin up forward and a galley sink by the companionway both on the starboard side. The drain from the basin runs under the saloon sofa, aft to below the galley sink where both flow into a shower sump type box with an orca bilge pump in it. This pumps out from the sump box, across the bilge to the port side, under the chart table, up the side of the hull to get round the battery box, in under the engine and then back to a through hull on the transom about 6 inches above the waterline.

The pump isn't automatic and also can't keep up if you empty the galley sink into the sump box, which of course isn't sealed and so leaks. Also when the box is empty and I turn the pump off, about 3 litres of water flow back through the long hose and this fills the box which leaks into the bilge.

Anyway I was wondering what the opinion on the forum was for the best new solution.

One option would be to install a seacock under the galley sink and connect both sink wastes to that.
Another would be to take the waste forward and tap it into the heads so it uses that seacock. (Not sure if that would solve the problem though as I'd have to decide which side of the heads raised loops to join it in.)
A third would be to keep using the through hull on the transom but to reroute the hose and install raised loops, non-return valves, replace the sump box with something waterproof. Etc, etc.

More modern charter boats I've been on tend to have extra seacocks for the sinks but I'd prefer not to cut extra holes in the boat so what set up other have.

PS - The boat is a UFO34 so has a very shallow bilge.

 

[prv]

I think I would certainly fit a new seacock directly below the galley sink. You say you have a shallow bilge so presumably the sink is well above the waterline and no problems with drainage. The forward basin could either tee into the galley sink pipe, or have its own separate seacock forward.

I wouldn't recommend sharing anything with the heads outlet. Even if it's unlikely given relative pressures etc, the risk of pumping sewage up into the galley would concern me.

Pete

 

[pvb]

New seacock.

 

[Stemar]

I agree with PRV about not using the heads outlet. I know you'd NEVER do it, but imagine a newcomer to your boat pumping the heads with the exit seacock closed. There'd be no resistance to warn them to stop, so off they go, enthusiasically following your rule about 20 pumps to make sure the outlet pipe's well flushed through...

I understand the pov that thinks skin fittings are the devil's work, but as long as there's a good, easily accessible seacock (I'd use Marelon) I really don't have a problem with them as long as the plug hole is above the waterline at all reasonable angles of heel. If that's the case, I'd fit one outlet for the galley and another for the wash basin. Sinks and basins have a habit of gathering stuff that blocks pipes, so IMO, the shorter and simpler the run the better.

If the plug holes are near the waterline, it's a different matter and an enlarged sump with an automatic pump would be my preferred solution. You could say, it's OK, I'll just close the seacocks when I go to sea, but I wouldn't. The anti-backfill loops on my heads were inadequate when I got her and I didn't know better. All was well for a couple of years because I religiously closed the seacocks. Until the day I didn't and, after a nice long starboard tack beat, I noticed the carpet in the saloon was floating in several inches of water. Cue some rapid bailing and a diversion to a port with running water to wash the carpet, followed a few days later by some revised pipework.