Is my head plumbed correctly?

[Kelkara]

I've been tracing out all the plumbing hoses on my new-to-me boat, but I think that the head is plumbed in wrong ... the flush handle sucks a lot of air, but I don't think there's a problem with the pump.

Before I do loads of uncomfortable boat-yoga reconfiguring it, can someone please confirm for me that the vented loop should be between the pump and the bowl and not between the seacock and the pump?

Also, the holding tank is completely inaccessible without cutting away a large part of the V-berth (which I don't plan on doing) - so there seems to be no way of telling how full it is (I don't even know if it is currently full or empty) - apart from counting flushes, any ideas for guaging how full it might be?

I'm also a bit concerned that the reserve fuel-tank vents inside the boat ... should I be?

[thinwater]

Originally Posted by Kelkara

I've been tracing out all the plumbing hoses on my new-to-me boat, but I think that the head is plumbed in wrong ... the flush handle sucks a lot of air, but I don't think there's a problem with the pump.

Before I do loads of uncomfortable boat-yoga reconfiguring it, can someone please confirm for me that the vented loop should be between the pump and the bowl and not between the seacock and the pump?

Also, the holding tank is completely inaccessible without cutting away a large part of the V-berth (which I don't plan on doing) - so there seems to be no way of telling how full it is (I don't even know if it is currently full or empty) - apart from counting flushes, any ideas for guaging how full it might be?

I'm also a bit concerned that the reserve fuel-tank vents inside the boat ... should I be?

Yes, you are correct. I was amazed (actually, given the way things have gone, barely surprised) when Sail Magazine published that same incorrect location a few months ago. The didn't even print a correction. All they needed to do was go on-line and look up vendor drawings, which I sent them.

Do that. Go to the Dometic site and they will show the correct location.

And yes, I would move the fuel vent location. That is a serious code violation.

[Pete7]

Blimey, that's complicated for a bog (toilet)

[Dave Lochner]

Originally Posted by Kelkara

I've been tracing out all the plumbing hoses on my new-to-me boat, but I think that the head is plumbed in wrong ... the flush handle sucks a lot of air, but I don't think there's a problem with the pump.

Before I do loads of uncomfortable boat-yoga reconfiguring it, can someone please confirm for me that the vented loop should be between the pump and the bowl and not between the seacock and the pump?

Also, the holding tank is completely inaccessible without cutting away a large part of the V-berth (which I don't plan on doing) - so there seems to be no way of telling how full it is (I don't even know if it is currently full or empty) - apart from counting flushes, any ideas for guaging how full it might be?

I'm also a bit concerned that the reserve fuel-tank vents inside the boat ... should I be?

You are correct, vented loop between pump and bowl, not pump and seacock.

Get the fuel vent out of the cabin and vent to exterior, to a place that won't allow water to get in.

The holding tank may not be a separate tank, but integral to the hull. Most plastic holding tanks have a clean out port on the top, a ~4" hole with a cap. You could install one of them. When the tank begins to get full you will smell it if it is vented. There are a number of different types of tank monitors out there, some use capacitance with 2 foil strips to sense tank level.

Get Peggy Hall's book on marine plumbing.

[pcmm]

Vented loop is in the right place, but the toilet discharge should not share the same seacock as the sink!

[Kelkara]

Thanks everyone - It's good to get the voices of experience - the head works a lot better with the hoses switched around.

Originally Posted by thinwater

And yes, I would move the fuel vent location. That is a serious code violation.

OK everyone seems agreed on that - totally on the To-Do list.

Originally Posted by Dave Lochner

The holding tank may not be a separate tank, but integral to the hull. Most plastic holding tanks have a clean out port on the top, a ~4" hole with a cap. You could install one of them. When the tank begins to get full you will smell it if it is vented. There are a number of different types of tank monitors out there, some use capacitance with 2 foil strips to sense tank level.

Get Peggy Hall's book on marine plumbing.

That makes sense - whatever the tank is, it has been there since the boat was constructed. Installing a port on the top might make sense in the future - the trouble with adding a tank monitor at the moment is that I have no access to the inside of the tank, and don't actually know if the V-berth fiberglass is the outside of the tank or not.

Peggy's book now on my wish-list.

Originally Posted by pcmm

the toilet discharge should not share the same seacock as the sink!

Yeah, that was another thing I noticed too. Since the head compartment is really too cramped to make using the sink practical, for the moment I'll hope that the check-valve remains closed, and not use the sink - In the future I guess I should T it into the flushing-water seacock.

[Brewgyver]

The hand sink drain should have its own through-hull. You do NOT want to tee it into the flushing water through-hull. If you did that, you would be right back where you started, because the head pump would suck air through the sink drain, and your head wouldn't flush. Check valves are also problematic in drain lines.

As to that fuel vent line, it should be on the done list, not the to do list. Hopefully you don't have a gasoline engine...

Edit: Now I see the fuel return line from the engine, so it's likely a diesel.

[thinwater]

Originally Posted by Brewgyver

The hand sink drain should have its own through-hull. You do NOT want to tee it into the flushing water through-hull. If you did that, you would be right back where you started, because the head pump would suck air through the sink drain, and your head wouldn't flush. Check valves are also problematic in drain lines.

As to that fuel vent line, it should be on the done list, not the to do list. Hopefully you don't have a gasoline engine...

Edit: Now I see the fuel return line from the engine, so it's likely a diesel.

What he said.

If the sink is significantly above the waterline, consider adding a through-hull above the water line. It has many uses, like draining a dehumidifier.

[jeepbluetj]

Or, share the sink drain with the head intake. If that's under the waterline, you can flush with salt water and/or drain the sink with the thruhull open. --OR-- close the thruhull, fill the sink with freshwater, and flush with fresh. (This idea is in Peggie's book too)

The head discharge should be on it's own thruhull.

[steamgoat]

Tartan 37's use the sink drain as the head inlet. If it sucks too much air,put the plug in. If you want to flush the head with fresh water,close the seacock and fill the sink with fresh from a tap.

[chris95040]

Originally Posted by Kelkara

I've been tracing out all the plumbing hoses on my new-to-me boat, but I think that the head is plumbed in wrong ... the flush handle sucks a lot of air, but I don't think there's a problem with the pump.

Before I do loads of uncomfortable boat-yoga reconfiguring it, can someone please confirm for me that the vented loop should be between the pump and the bowl and not between the seacock and the pump?

Also, the holding tank is completely inaccessible without cutting away a large part of the V-berth (which I don't plan on doing) - so there seems to be no way of telling how full it is (I don't even know if it is currently full or empty) - apart from counting flushes, any ideas for guaging how full it might be?

I'm also a bit concerned that the reserve fuel-tank vents inside the boat ... should I be?

I might be remembering this wrong, but I'm pretty sure the electric Jabsco head I had years ago had no way to install a vented loop between the bowl and the pump. It had to be between the intake seacock and pump, which obviously doesn't work... Their workaround was an electric (solenoid) vented loop that would disable the vent when powered up.

Not sure if this is relevant to what you've got going on.

[peghall]

I'm still not sure how your toilet is plumbed, so I'm just gonna tell you how it SHOULD be. Yes, the INTAKE vented loop belongs between the pump and the bowl. It needs to be at least 6-8" above waterline at ANY angle of heel...which on most sailboats puts it 2-3 FEET above the bowl. If the toilet is plumbed to flush directly overboard, there should also be a vented loop in the toilet discharge line...it needs to be as high as the intake thru-hull. The toilet discharge should be on it own thru-hull, aft of any intake thru-hull.

However, the toilet INTAKE *can* share the head sink drain thru-hull (Tartan and a few other builders used to plumb it that way to eliminate one hole in the boat, not to mention the cost of the seacock). The toilet intake line has to tee into the sink drain line below the waterline, as close to the seacock as possible. If your toilet intake is plumbed this way and the tee is close to the waterline, it may be pulling in air through the sink. If so, keeping a plug in the sink except when actually using the sink should solve that problem (rubber sink plugs in all sizes are inexpensive and available from most hardware stores)

As for access to your holding tank... You NEED access to the tank to know whether the hose connections are sound and what the hoses are connected to at their others ends. That'll also allow you to install a tank level indicator. But sooner or later you're gonna need access anyway, because the time will come when you'll have to replace all the hoses to and from it...maybe even sooner if you have to remove a blockage from the vent line.

The easiest solution: open up access from the top. Hopefully the "platform" on which the mattresses rest isn't the top of an integrally molded tank. If it's not, it's a simple matter to cut out whatever supports the mattresses and if necessary replace it with plywood you'll be able to just lift out when you need to. Just make sure you're not removing anything structural to the boat.

Btw...what's the make/model/approx age of your toilet?

Peggie
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

[Kelkara]

Thanks Peggie,

I guess that's the definitive answer then. My toilet is a Jabsco manual toilet, and probably only a few years old. The previous owner obviously didn't read your book, since there is no vented-loop on the overboard discharge - another task for the to-do list.

I'll keep investigating the holding-tank - it must be possible to at least access the hose fittings, because the current hoses are not that old, so must have been replaced at some point - but it sure would be nice to know what's hiding back there.

I thought I was asking a pretty dumb question, but so far you guys have added the following to my to-do list:

a) Move the intake vented loop [done]
b) Tee the sink drain to the intake seacock.
c) Install a vented loop on the outflow seacock.
d) Locate holding tank and add an inspection port.

not to mention

e) Add external vent for reserve diesel tank

[Dave22q]

Beg,borrow or buy a cheap (under $100) inspection camera, cut a 1" hole under the V mattress and you can locate your tank. Then you can jigsaw an access hatch. I find it hard to believe that any designer would sacrifice the significant storage space in the bow as well as foreclose the necessary access to the holding tank so this situation may be the work of a prior owner but I lack the imagination to come up with a reason to do so. Good luck with your investigation.

[pcmm]

Get a cheap USB endoscope type camera. We purchased one from "gearbest" and yes its cheap with OK (VGA) resolution but it came on the end of a 5m cable with little LED lights and it cost $15 delivered!! works with both our tablets and laptops. Its one of the best "boat tools" to date!