Sink Drain question? trap or No trap?

*When I purchased this boat, the PO had used a chemical basin to "de-humidify" the boat.* He had placed this in the stainless steel sink.* This chemical ate through the steel of the old sink.* The PO took the old sink out and I see no evidence where there were "traps" in the sink drains, just straight tubes.* The question is, when plumbing the new sink in, it seems to me that traps may be necessary.* (Damn' this is so new to me. I associate the boat with home ownership)* I don't even know where the sink drains too?* Yes, I am a novice, but I'm learning!* So the question is...... Traps or NO traps?*


-- Edited by Sam on Tuesday 13th of March 2012 02:13:53 AM

Thought traps were to prevent vapors/gasses from the sewer line.* Don't see any need for a trap if your sink drains directly into the ocean/bay/whatever.

So Mark, are you telling me that as a standard, the boat's sinks do not drain into the sewage tank, but into the ocean/bay/whatever?* (As I said, I'm new to this.* Lots of*quesitons..... and yes, there*may be such a thing as a stupid question)


-- Edited by Sam on Tuesday 13th of March 2012 02:42:43 AM

"are you telling me that as a standard, the boat's sinks do not drain into the sewage tank, but into the ocean/bay/whatever? "

Same for shower water ,

World wide direct overboard is done , but somewhere there may be a drinking lake that does restrict "grey" (sink) water.

Usually only "black" water , toilet water, is required to be "properly disposed of" , a holding tank and a pump out or sea disposal.

There is no purpose to a trap with direct overboard sinks.

Tho in theory it could save metal dropped into the drain , wedding ring?

Greetings,
Mr. sam. Welcome aboard. Ah yes, the wonderful world of boating...In some ways, a boat IS like a land bound home but there are enough systems specific to a boat that will cause you to generate a myriad of questions-ask away. Everyone on here started afresh at some point.
As mentioned, if you drain overboard, no trap BUT that drain hose should have a freely operating seacock next to the hull to seal your hull penetration even if said penetration is above the water line.
SOME household equipment can be used on board as evidenced by my question concerning GFIC outlets in the recent past (general consensus was household unit was OK) but other "stuff" is a no-no. Non ignition protected automobile equipment on a gas fueled vessel for example. Enjoy...

On most boats, sinks drain directly overboard and no trap is necessary because there are no sewer gasses to contend with. There are some inland lakes in the USA that prohibit discharge of not only sewage ("black water"), but water used for washing, showering, etc. ("grey water"). Boats built for these areas will have holding tanks for black water and holding tanks for grey water. In this case, traps under sinks and showers are necessary.

I disagree with RTF, I don't believe seacocks are necessary for openings above the waterline. You wouldn't want to climb into the bilge to open a seacock just to wash your hands and then climb back in afterwards to close it.

Greetings,
Interesting comment Mr. rwidman. Any other opinions regarding "seacocking"?

What they're all telling you is correct--no traps needed in any plumbing on a boat. In fact, traps actually create problems.

As for seacocks on above-waterline thru-hulls.... Monohull sailboats definitely need 'em--along with vented loops--because heeling can put thru-hulls below waterline. However, on a boat that cruises upright (or is designed to do so anyway), whether they're needed depends on several factors. Never on a bilge pump thru-hull... Always on a thru-hull that's only a few inches above waterline, 'cuz a strong wind can push water over the top of it, and into it ( and was what sank a friend's boat in its slip one night). If you cruise offshore where you can find yourself in heavy seas that keep decks awash for a day or even longer, seacocks are a good idea, even on tank vent thru-hulls.

I've always been a firm believer that it's hard to go wrong erring on the side of caution. But it's really up to you and your comfort level.

Hi there Peggie...

We have seacocks on our bilge pump through hulls, which are always left open. The purpose of the seacocks is to be able to close them in the event of a hose failure etc. (The through hulls are fairly close to the waterline.)

Similarly we have always open seacocks on our sink drains, that are only in place in the event of a hose failure, as again the through hulls are fairly close to the waterline.

Seacocks on sink drains come in very handy for cleaning the drain, 'cuz it allows the drain line to hold water. Just close the seacock, add an ounce or two of Raritan C.P., fill with water and walk away at least overnight--although C.P. can remain in a drain or sump indefinitely without harm.

Bilge pump thru-hulls too close to the waterline can result in taking on water using an effect known as "ram water"--water forced (rammed) up a line by the pressure of the hull against the water when the boat is underway. The bow wake on my own Trojan F32 kept my forward bilge pump running non stop when I was underway because the thru-hull was too low. So if you need a seacock on that one to protect against a failed hose, that thru-hull needs to be moved, which is how I solved the problem on my own boat.

Fwiw, hose connections failures rarely happen without plenty of advance warning that one is about to happen--a failed hose clamp...an over-age hose that's cracked... Regular inspection and repair does a lot more to keep boats afloat than seacocks that someone forgot to close.

I was told by a very experienced boater to put traps in so CO could not enter through the drain if I was in a raft up with a gas boat running the engine or generator. I thought it was an unlikely entry point but put one in the head because it was easy. Have not put one in the galley.*

I once fished a contact lens out of the trap for my wife! Bonus points for the evening!

*

Rob

37' Sedan

Ever though a trap is not needed I have a slight bend/trap on all sinks as my wife keeps dropping her rings down the drain.* My ring will never come off because when we got married she saw I could take it OFF, so she*took it back and had*made smaller and extra tight.* However the nose ring did fit to her satisfaction.

*

*



-- Edited by RT Firefly on Wednesday 14th of March 2012 08:43:03 PM


-- Edited by RT Firefly on Thursday 15th of March 2012 08:12:44 AM

That link doesn't work, RTF. Says "Forbidden". Must be good.

Keith wrote:
That link doesn't work, RTF. Says "Forbidden". Must be good.

If you shorten it to http://www.godlikeproductions.com/*you will find it's a forum for really strange people.

Click to expand...

*

Tried that link and it says my IP address has been banned from the site. And I've never even been there! Must be some paranoid **** in there.

Greetings,
I've deleted said "verboten" web site. My post was simply a harmless, innocuous comment on nose rings. Yup, GLP is somewhat off the wall and populated, as Mr. rwidman suggests, by "really strange people". On the other hand, a LOT of the sites I visit are popular with a variety of "strange" people. Present company excepted OF COURSE!!!!! Didn't mean to TRAP anyone....hahahaha


-- Edited by RT Firefly on Thursday 15th of March 2012 08:20:10 AM