Seacocks doing double duty??

[JeremyFowler]

And another question too please, I’m trying to do away with as many holes in the hull as possible, simplify, simplify, simplify.
Can I use the same seacock for entering engine cooling seawater AND for exiting greywater from the kitchen sink? A bit of soapy water going through the raw water strainer once in a blue moon shouldn’t cause any problems, I’m thinking. Yes? No?
Thanks for your thoughts.

[Sailmonkey]

No.

The possibility of pulling air trough the sink drain is too high, as well as the clogging of the heat exchanger cooling passages with bacon grease and the like.

[Fuss]

Originally Posted by JeremyFowler

And another question too please, I’m trying to do away with as many holes in the hull as possible, simplify, simplify, simplify.
Can I use the same seacock for entering engine cooling seawater AND for exiting greywater from the kitchen sink? A bit of soapy water going through the raw water strainer once in a blue moon shouldn’t cause any problems, I’m thinking. Yes? No?
Thanks for your thoughts.

You have to think not from the perspective of the sink water draining through the same seacock but that the motor is sucking water from the sea. When your sink drain is connected then it is much easier to suck air from your sink than water from the sea.

[mako]

Also your sink drain should exit the hull above the waterline - usually in the boot stripe. That is not a hull penetration of high risk

[rslifkin]

Originally Posted by mako

Also your sink drain should exit the hull above the waterline - usually in the boot stripe. That is not a hull penetration of high risk

That only works if the sink is high enough above the waterline. Not the case on some sailboats, so they dump below the waterline.

[pcmm]

Originally Posted by mako

Also your sink drain should exit the hull above the waterline - usually in the boot stripe. That is not a hull penetration of high risk

That would be exceedingly rare. Ideal yes, but rare. I've yet to see a boat with the sink drain above the waterline. Cooling water (A/C, etc.) bilge pumps, etc. Often too I see bilge pumps exit far too close to the waterline. Bilge pumps should exit as close to the sheer line as possible ( you want that to be able to discharge no matter what.)

Seacocks generally should not do double duty as having to close one seacock can cause you to loose 2 "items". The best solution if you want to reduce seacocks is to have a "sea chest" for all your intakes (though I would still have the engine on its own)

[Ded reckoner]

I think your goal is to reduce the number of thru holes. This doesn't necessarily mean reducing the number of seacocks. Caliber sailboats have a single large thru hole instead of holes for each purpose. A manifold with a bank of seacocks allows selection of functionality and enables seacocks be provided for each purpose. I think their solution could be yours.

[zstine]

Originally Posted by Ded reckoner

I think your goal is to reduce the number of thru holes. This doesn't necessarily mean reducing the number of seacocks. Caliber sailboats have a single large thru hole instead of holes for each purpose. A manifold with a bank of seacocks allows selection of functionality and enables seacocks be provided for each purpose. I think their solution could be yours.

just an FYI, The "manifold with a bank of seacocks" is called a "sea chest" as pcmm discussed above.


I agree that mixing a sink drain and engine in is a no-no. You can 'T' some things together though. I have my head flush water input and the head sink drain "T' together. It nicely allows for fresh water flush or seawater flush. Always fresh water flush before leaving the boat for a while as Seawater stinks it up!

[vpbarkley]

If you have a sea chest it is for water entry only. You don't discharge into it.

[ohthetrees]

My production boat (Hanse) has under water thru hulls for galley sink drain, aircon, and generator cooling water (exhaust gasses are above waterline).

Regarding thru hull sharing, you might get away with it with things that are “clean“, (maybe aircon?), but I definitely wouldn’t for a galley sink drain. Our galley drains under the waterline, and when I dive the bottom I could see a big fan of grease adhered to the hall around the thru hull opening. I wouldn’t want that stuff in my engine.

[Fore and Aft]

Jeremy I have our toilet inlet plumbed into the head sink outlet. It works well and you can turn the seacock off and flush the toilet just using fresh water in sink. I also have the galley saltwater tap teed of the engine water strainer. It works well, but when motoring its a bit harder to pump.
Cheers

[JeremyFowler]

Hearty thanks to each of you! I never even thought of the air suction issue I must confess...
Another confirmation of the Biblical quote: "There is safety in a multitude of counsellors".

[Mike Banks]

No. Never do anything like having an inlet and an outlet to the sea from the same through-hull.


If you wish to limit the number of through hulls you can use stand-pipes. These are connected to through hulls, usually larger sized ones, and go from the through hull fitting or hull itself in the case of metal or glass boats--up to above the water line. Some of them if made of metal or fibreglass pillars and welded or glassed in place can double as supports for furniture or even the mast or deck beams. Into these stand pipes, one for sea water inlet, one for waste water outlet, are plumbed all of the other fittings and sea cocks--and at the top there is usually a port so that a clearing rod can be used to push any obstructions or growth back out of the bottom of the pipe. Always put the inlet stand pipe for'ard of the outlet pipe.

[lordgeoff]

Originally Posted by JeremyFowler

And another question too please, I’m trying to do away with as many holes in the hull as possible, simplify, simplify, simplify.
Can I use the same seacock for entering engine cooling seawater AND for exiting greywater from the kitchen sink? A bit of soapy water going through the raw water strainer once in a blue moon shouldn’t cause any problems, I’m thinking. Yes? No?
Thanks for your thoughts.

Noooo