head plumbing questions

OK, time for everyone's favorite topic: poo!

I'm re-plumbing the water supply for my boat's head. The original system had one seacock that fed raw water to both the manual pump head and the pump for the air conditioner. I've long had problems with keeping a prime on the AC pump and odors from the head. I've decided to re-work things so that the head pulls fresh water from the storage tank, and the AC pump is the only thing fed from the seacock. AC plumbing is cake, and in fact its already done. The water supply plumbing is where I have questions.

Right now as a trial fit, I've got a T at the fresh water tank. One side of the T goes to the water pump, the other side goes to the head. The water pump works fine, I have normal flow from the faucets. I can't get the head to prime though. The manual Jabsco pump has to lift water maybe 18" at most from the bottom of the water tank to it's supply fitting. Should it be able to pull that high without issue, or have I got issues with the head pump? The original seacock is right next to the freshwater supply and it pulled from that without issues.

Secondly, what sort of check valving do I need here? AM I ok with a simple one-way foot valve on the line to the head in order to prevent the fresh water pump from pulling anything nasty back, or do I need something more elaborate? The head is NOT on the pressure side of the fresh water pump, its on the suction side.

Thanks in advance for any tips!

Re: head plumbing questions

Nobody has ever re-plumbed a head before?

Re: head plumbing questions

My Rinker 242 did get water back into the head when I would cruise around. All I did was replace the joker valve ($10) and all was well and no smell. I do not know why you would want to pull water from your fresh tank when sea water is unlimited. There is an extreme chance of contaminating your fresh tank with back flow that will happen and that is the main reason folks do not re-plumb. Check on the Rinker forum or at www.rinkerboatowners.com. I wish I could answer the AC issue because I would love to have AC in my cabin. The folks on the Rinker forum can answer that.

Re: head plumbing questions

the problem I have with seawater in the head is the odor it causes from all the bacteria in the water. If I flush it with fresh water, the boat doesn't stink. 10 minutes with the hatches open fixes it, but the hours of complaints I have to listen to is not so easy to get rid of if you get my drift.

I've also had a lot of problems keeping a prime on the AC circ pump. It draws air backwards through the head due to the shared seacock, and its a pain to get it to go again. I've had it stop pumping out of the AC by flushing the head too. That problem could be fixed by just adding a second seacock, one for the head and one for the AC, but there just isn't any room down there. The incredibly tiny utility access area is just loaded up with junk I can barely reach as it is, and there isn't any spot that I can punch through the hull for a second valve. I'd really just like to flush the head with fresh water if I can. We aren't on the hook all that much, and we don't use the fresh water for drinking anyway. Its for showers and washing dishes mostly. I don't mind adding check valves or whatever it takes to get this done, but I'm just not 100% sure what I need. If its nothing more than a standard swing check valve, I can do that easily. If I need something more involved, I just need to know what to buy so I can install it.

Re: head plumbing questions

It is an expensive option but if you want a fresh water system check out going to a vacu flush system.

Re: head plumbing questions

Do you have room for a separate fresh water tank for the head? I think there is too much chance of cross-contamination in a marine environment with just a simple foot valve. It would require a vacuum breaker, air-gap, reduced pressure zone backflow preventer or some combination of them to be sure if you used the same tank. Without seeing the set up you have now it is hard to say why it isn't working as you tried to hook it up.

Re: head plumbing questions

The head should not have standing water in it normally. You flip the valve lever to the left and pump until there is water in the bowl. Do your business and pump until said business is gone. Then flip the lever back to the right and pump until empty. It should stay empty. If not you are getting back flow from the holding tank / hose and your joker valve has gone bad and just replace that. I cannot help you with the prime on the AC.

Re: head plumbing questions

I don't have room for a seperate water holding tank. As it is, I can barely get to the one I have. Replacing it would involve cutting the floor out of the head. Theres no spot for a second one unfortunately. Exactly what parts do I need to do this though? You mentioned a vacuum breaker and some other things?

Ditto on the vacu-flush. Absolutely no room to install the hardware. I'd like to go with a sanitation system and do away with the tank entirely. Actually I'm about 95% sure the real problem is the tank and/or hoses are bad, but I can't convince anyone else of that.

Its not a problem with standing water in the head. The boat just stinks like "business". The head itself remains dry but the cabin has a smell to it. My folks have been told by others that the problem is caused by flushing the head with seawater instead of fresh water. Something about the bacteria in the seawater breaking down the leavings in the tank and making it smell. Doesn't add up if you ask me, any gas produced should be going out the vent. The vent is not clogged and it does work so thats not the issue. Pretty sure the hoses have gotten porous or the aluminum tank has a slight leak after 16 years and its just due for replacement. This head plumbing nonsense is just so I can say I've done everything possible, and that the real problem lies elsewhere.


I know what the AC problem is. Its sharing one seacock with the head. It sucks air backwards through the head's hand pump instead of air, and I lose my prime. REmoving the head from the AC plumbing fixed that, so thats not a problem anymore. I just need to know how to properly hook up the head now. If I ever do go back to raw water feed, I'm pretty sure i can just insert a one-way check valve on the head side of the T and fix the air problem too.


And before anyone says it, yes I am very well aware that "fixing" something that isn't broken just to appease people makes no sense and is an incredible waste of time and money. I know this is dumb and my efforts are better spent elsewhere but if I can get this plumbing nonsense done, prove that the smell was not caused by seawater and get them to seriously consider dealing with the real problem I'll be well ahead of the game. Eight years I've been trying to make the sale of new hoses and a new holding tank, and I'm hoping this will be the final nail in the coffin of denial.

Re: head plumbing questions

Well if your sure, stick to your guns and you will get the parts you need.

Re: head plumbing questions

The sea water that you are presently using is the cause of the bad odours. The micro-organisms in the water die and start to stink within hours of being pumped through the plumbing system.

My suggestion would be to replace the toilet with an electric version that uses fresh water from the pressure side of the freshwater system to flush. It will eliminate 90% of the holding tank odour and separate the system from the AC.

Re: head plumbing questions

stagnant sea water will develope a terrible smell after a few days, when you leave the boat for a while just flip the lever to dry bowl, pour in 1/2 gallon of fresh water with 1/2 ounce of bleach added and pump out . you will have no odors

Re: head plumbing questions

siple fix is to use this http://www.iboats.com/Sealand_Holding_Tank_Deodorant/dm/*******.900799977--**********.877039926--view_id.47324 in your tank at all times and pump out at the end of each day that you use your head immediatly after pumping out add traetment.