Fresh water flush for head

Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
Has anyone replumbed their head intake to the sink drain? That's a pretty common technique in the C30 and C27 world. It lets you use fresh water from the sink to flush the head, and really reduces the smell that can be caused by seawater going septic in the inlet hose. If you don't want to use fresh water you can always open the sink drain seacock and use seawater.

Seems like a pretty easy thing to do, but I haven't seen anything about it on the forum. Maybe there's a good reason not to do it?
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
no it's a good thing........ i did it to my boat ...and Peggy Hall endorses it to the max when at all possible do a search on the subject and type Peggy Hall or Headmistress in the search for the author
 
Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
Good to hear. I've got Peggy's book, and have had several discussions with her about our Catalina 27.
 
Dec 2, 1997
8,946
- - LIttle Rock
Teeing the head intake into the head sink drain has also been well discussed here on sailboatowners.com Search for "Sea water intake odor cure" in the plumbing and sanitation forum archives. It's a great solution...in fact, some boat builders did that because it eliminates one hole in the boat and also saved them the cost of a seacock.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Ahh, yet another project I intend to do but haven't gotten to yet. I have all the parts on board.

The potential problems I have found so far is first getting the hose from the T under the sink to the head pump. You might need to drill a hole depending on how Catalina did your install. Second, and more significant, is the Marelon thruhulls. The hose barb is a fixed to the unit so you can't remove the barb to put at T and two barbs directly on the thruhull. This means your only option is to put a T in-line in the hose. This is a less than ideal installation. Having a T in the hose below the waterline is a risky move and some insurance surveyors may call this out as an out of compliance installation.

I plan to repurpose the head intake thruhull for a deck wash down pump and later a water maker.

Please post some pics if you get to the project before me.

Good luck and fair winds,

Jesse
 
Dec 2, 1997
8,946
- - LIttle Rock
The hose barb is a fixed to the unit so you can't remove the barb to put at T and two barbs directly on the thruhull. This means your only option is to put a T in-line in the hose. This is a less than ideal installation. Having a T in the hose below the waterline is a risky move and some insurance surveyors may call this out as an out of compliance installation.
You're over-thinking this, Jesse... What's the difference between a tee in a line below the waterline and a y-valve? A shutoff valve? They're all over place in holding tank installations. in In 25 years, I've never heard of a single surveyor who had a problem with it. Nor would boat builders like Tartan have plumbed using a tee in the line if it could cause a problem. They do a LOT of really dumb things in their sanitation system installations, but never anything that could put 'em at risk for a liability claim in a a sinking. Just be certain that all connections are double clamped, with the screws 180 degrees apart...or at least 90, if 180 is impossible.
 
Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
Teeing the head intake into the head sink drain has also been well discussed here on sailboatowners.com Search for "Sea water intake odor cure" in the plumbing and sanitation forum archives. It's a great solution...in fact, some boat builders did that because it eliminates one hole in the boat and also saved them the cost of a seacock.
Thanks Peggie. I only posted in this forum because I wanted to know if there were any C310 specific issues. The plumbing and sanitation forum is a great resource, and I've taken advantage of it before.
 
Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
Ahh, yet another project I intend to do but haven't gotten to yet. I have all the parts on board.

The potential problems I have found so far is first getting the hose from the T under the sink to the head pump. You might need to drill a hole depending on how Catalina did your install. Second, and more significant, is the Marelon thruhulls. The hose barb is a fixed to the unit so you can't remove the barb to put at T and two barbs directly on the thruhull. This means your only option is to put a T in-line in the hose. This is a less than ideal installation. Having a T in the hose below the waterline is a risky move and some insurance surveyors may call this out as an out of compliance installation.

I plan to repurpose the head intake thruhull for a deck wash down pump and later a water maker.

Please post some pics if you get to the project before me.

Good luck and fair winds,

Jesse
I've got a nice hole there already. It's also easier to get at the sink valve, compared to the normal head intake valve, I think.
 
Aug 7, 2007
76
- - Oyster Bay, NY
Just a suggestion but we use the hand held shower head as a water source for the head. Do your business, shoot water into head and pump.
 
Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
Just a suggestion but we use the hand held shower head as a water source for the head. Do your business, shoot water into head and pump.
I agree that is an easy way to flush the bowl and outlet line with fresh water, but that doesn't help with the seawater sitting in the head intake line. If you never pump wet then whatever is in that hose is going to get real smelly.
 
Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
If you look at this link, you'll see we didn't even need a T, we simply swapped out the shower sump and the head inlets.
Unfortunately the C310 is plumbed differently. The shower sump goes (I think) under the galley sink, although I still haven't traced it all out yet. The plumbing diagram form the Owner's manual doesn't match what I see.
 
May 3, 2008
190
Catalina 310 Catawba Island
Hopefully we will get pics and steps involved in connecting the sink drain to the head pump from someone who does this modification. I am using the shower method and Stu's advice is interesting.
 
Nov 16, 2012
1,055
Catalina 310, 2000, #31 31 Santa Cruz
My Catalina 27 didn't have a head sink, so I added a tee and another valve to the head inlet thru hull. A short piece of hose (and being certain to never open both valves at the same time!!) let me pump fresh water from a bucket to the head at the end of the day/weekend. No smell!

I'm looking forward to doing it on the C310, with a simpler, more secure setup.
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
Hopefully we will get pics and steps involved in connecting the sink drain to the head pump from someone who does this modification. I am using the shower method and Stu's advice is interesting.
i already posted a pic of that set up and all you do is put a hose barb into the tee that was added to the sink drain hose or on top of the sea cock ball valve for the sink drain to feed the head water supply line on you head and you have it ...you can add a strainer in that line if you like
 
Last edited:
Dec 2, 1997
8,946
- - LIttle Rock
[QUOTE="woodster, post: 1247399, member: 91727] "... all you do i put a hose barb into the fresh water supply line on you head and you have it ...you can add a strainer in that line if you like[/QUOTE]

I hope you DO meant the FLUSH water supply line, NOT a line in the potable (fresh water) system...'cuz connecting any raw water toilet to the onboard fresh water system is a BIG no-no!