Options to Convert to Fresh Water Flush

May 25, 2013
36
Beneteau Sense 50 Waterford Harbour
My wife and I live aboard our (new, 1 year old) Beneteau Sense 50 in Houston (Waterford). Not long after we splashed the boat and began the liveaboard life, the forward head began to carry a smell. It seems to be the rather long sea water intake line. The other head has never smelled and it has a pretty short run from the thru-hull to the head.

Short of installing a Raritan Sea Fresh system with all it's bells and whistles, what do you recommend to convert that head to a fresh water flush and maintain a fresh/salt water selection? I would prefer a safe way to utilize the water from one of the tanks.

I had a quote of around $2000 (parts and lots of labor) to install the Raritan system.

Thanks.

PS. Just ordered your new book.

Bryan (Captain Ag)
 
Jan 1, 2006
7,570
Slickcraft 26 Sailfish
You can buy a lot of gallon water containers for $2000! In fact you can use one for a long time and refill it from the ship's water supply which needs to run and to turnover anyway. Someone posted a reason not to do this but I don't remember the reason. We did it for years. You can figure how much volume it takes to clear the discharge line and always use that amount. Yes, you'll have more pump outs but that's good.
 
Dec 19, 2006
5,832
Hunter 36 Punta Gorda
I did add a spray like on a home sink or RV in tiolet and hooked the sprayer into
the sink cold water and also have sink drain into head more info in this forum.
Been doing this many years now.
Nick
 
Jan 18, 2016
782
Catalina 387 Dana Point
The classic "easy" way that is also sanitary is to tee the head intake into the sink drain below the waterline. So if the thruhull is open, you get seawater flush. Close the thruhull, and you'll flush with water you run into your sink. Yup, you do need to run some water in the sink.
 
Feb 26, 2004
23,037
Catalina 34 224 Maple Bay, BC, Canada
The classic "easy" way that is also sanitary is to tee the head intake into the sink drain below the waterline. So if the thruhull is open, you get seawater flush. Close the thruhull, and you'll flush with water you run into your sink. Yup, you do need to run some water in the sink.
And you only need to do this for the LAST flush of the day (for weekend warriors). but since you're living onboard and have this smell, it's seems to be because you're not using it enough. Whenever we're on the boat and the head is being used regularly, there is NO smell.

We've T'd the head inlet into the head sink discharge.
 
Dec 19, 2006
5,832
Hunter 36 Punta Gorda
Could be the long run of hose was not getting flushed out with clean water regularly and now the smell or urine or poop is in the hose and may need to be changed.
nick
 
Dec 2, 1997
8,941
- - LIttle Rock
Jeep gave you the best option: tee your head intake line--which should then become a MUCH shorter line--into your head sink drain line below the waterline as close to the seacock as possible. That will allow you to continue flushing with sea water, but also provide the means of rinsing the sea water out of the entire system--the intake line, the pump, channel in the rim of the bowl AND the discharge line--with fresh water...just close the drain seacock, fill the sink with clean fresh water, flush the toilet. Water poured into the bowl just goes out the bottom of the pump and down the toilet discharge line. You can read about it in detail when my book arrives.

Converting your toilet to the Sea Fresh system isn't as simple as just adding it to your existing toilet.... first it would require replacing the toilet with either the Marine Elegance or the Atlantes--both of which are designed to use onboard pressurized flush water, so they don't have intake pumps. So to use sea water, you'd need to add a remote intake pump and separate sea water intake plumbing. Once you have all that, THEN you can add the Sea Fresh system, which consists of all the wiring, relays and switches necessary to let you switch between sea water and fresh. And THAT's why it's so expensive! Teeing the head intake line into the head sink drain line will does everything you want the Sea Fresh system to do for the price of a PVC tee or wye and a couple of hose clamps.
 
Aug 16, 2009
1,000
Hunter 1986 H31 California Yacht Marina, Chula Vista, CA
Jeep points out that the tee from sink drain to head intake has to be below the water line.
If the seawater seacock is closed doesn't the head have to pull the fresh water from the sink drain?
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
[QUOTE...If the seawater seacock is closed doesn't the head have to pull the fresh water from the sink drain?[/QUOTE]

That's the idea of teeing. If the seacock is not totally below waterlevel the head will mostly just suck air from the empty sink. On mine, even with the seacock open, the head will suck air and some water. Put the plug in the sink drain, and the head will suck water like it should.
 
Dec 2, 1997
8,941
- - LIttle Rock
Jeep points out that the tee from sink drain to head intake has to be below the water line.If the seawater seacock is closed doesn't the head have to pull the fresh water from the sink drain?
Assuming there's any water in the sink for the toilet TO pull out...yes. That's the whole point of teeing the intake line into the sink drain line: to provide a safe source of fresh water to rinse out the system.

It also provides another advantage to owners in climates where it's necessary to winterize: just pour the antifreeze down the sink and flush it through the entire system...you're done.
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
one more thing this set up will let you do is flush odorlos through the bowl after flushing with freshwater
 
Dec 19, 2006
5,832
Hunter 36 Punta Gorda
I like my fresh water sprayer next to my sea era and I got the idea from my RV
and the reason I like it is it controls how much water I add to the head when out cruising
with less trips to pump out,I also have the tee into the head to flush out the inner
system and keep smells out.
I could also use sea water to flush if out where can't get fresh water in my tank.
Just my little helpful idea and the sea era can be used dry pumping with out damage.
Nick
 
Aug 16, 2009
1,000
Hunter 1986 H31 California Yacht Marina, Chula Vista, CA
Peg, that's what I thought. You have to run the sink to provide the fresh water flush so that as long as there is water in the sink drain line, there will be something other than air for the head pump to pull. I assume that since the sink is higher than the head intake lines, that line should have some fresh water in it whenever the sink is used.
 
Dec 2, 1997
8,941
- - LIttle Rock
You're right that any water in the drain line will remain in it to the boat's waterline. However any fresh water left in the line will quickly be replaced with sea water the first time you flush the toilet with sea water.

And btw...don't even THINK of using gray water from the sink to flush the toilet. You'd be trading in one problems for a whole set of new ones because "used" sink water is full of soap scum, body oils, toothpaste, whatever dirt is washed off you, that you don't want in your toilet pump or discharge hose. For that reason, you want to run enough clean water down the sink after use to leave only clean water in the drain line.
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
You can buy a lot of gallon water containers for $2000! In fact you can use one for a long time and refill it from the ship's water supply which needs to run and to turnover anyway. Someone posted a reason not to do this but I don't remember the reason. We did it for years. You can figure how much volume it takes to clear the discharge line and always use that amount. Yes, you'll have more pump outs but that's good.
You know he IS talking about a half-million dollar boat........ ;^)
 
Feb 26, 2004
23,037
Catalina 34 224 Maple Bay, BC, Canada
You have to run the sink to provide the fresh water flush so that as long as there is water in the sink drain line, there will be something other than air for the head pump to pull.
Yup. I close the seacock, fill up the sink, and pump til it's dry.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
In Peggy's reply #15 where she mentions "soap scum"... Ten years ago I spent a week on an IP 38. The wife told me 'no bar soap', saying that the same stuff that coagulates the soap into hard bars will also coagulate the grey water to stick in the plumbing. You can see that effect in the home bath tub and shower walls. Every since, have only used (Dial 'Spring Water') liquid soap on the boat and at home with next to no buildup. I recently discovered the foaming soap, and that maybe be better yet. YMMV.
 
Oct 9, 2008
1,742
Bristol 29.9 Dana Point
I have selectable sea or fresh water flush. And it didn't cost me a penny, nor did I have to modify anything.

Similar to shemander, but simpler: I use a small plastic coffee can, which lives in the cabinet behind the head, and fill it with pressure water from the basin a foot from the head. Pour into the bowl and flush, with the flush selector on dry. The can holds just the right amount for a flush. Easier and faster than having to turn valves and seacocks under cabinets.
Put the lid back on the can and stow it.

BTW, possibly unrelated, and likely already widely known: After flushing, if you put just enough fresh water back in the bowl to cover the discharge hole, it will prevent odors coming up from the interior of the discharge hose and holding tank, if there are any.
 
Last edited:
Feb 26, 2004
23,037
Catalina 34 224 Maple Bay, BC, Canada
Pour into the bowl and flush, with the flush selector on dry.
Head Pumps 101 Why just pouring water into the bowl is NOT a good idea http://c34.org/bbs/index.php/topic,5865.msg40604.html#msg40604

BTW, possibly unrelated, and likely already widely known: After flushing, if you put just enough fresh water back in the bowl to cover the discharge hole, it will prevent odors coming up from the interior of the discharge hose and holding tank, if there are any.
That's not how marine heads work.