Head Hose Loops - Necessary ?

[AllezCat]

Hi All,
So I have a vacuflush head and Sealand holding tank system in the bilge.
There are 2 independent thru hulls:
One line is form the head to thruhull #1;
The other line is from the holding tank to thruhull #2.
But, both 1 1/2" head hoses run from the bilge amidships aft, then up above the waterline directly below my pillow.
It really stinks. probably from the previous owner(can't be from me).
So I intend to reroute the lines forward under the bathroom vanity(same height).
This is going to be a shitty job.
Just wandering if the above waterline loops are even necessary?
or mandatory?
Also while checking this I found the vent line runs downhill before exiting somewhere(still looking)...This could be a problem too, yes/no???

thanks for your help...

[CDunc]

Allezcat,

The ventedloops are needed to prevent syphoning water into your boat from the thru hulls, make sure its above the waterline at your most heeled angle when sailing. The vent line that goes back down could be your issue, I would look for where it goes back up it could be trapping water in the bend therefore not letting the gasses from the holding tank out. You can also by a filter to install on your vent line to reduce the smells. On mine I took the little valves on top of the vented loop off because they fail often and attached tubing to the vented loop valve stud and then conneted it to the vent tube below the thru-cabin house vent fitting.

[Ocean Girl]

Is your tank under the vberth?
MY 2cents -You do not need a vent between your holding tank and head (as long as your tank is vented) but do be sure to route the hose so it cannot dump the tank contents into your head when on a heel (dont rely on your joker valve to keep all that stuff at bay). Here is a great link that our wonderful friend Gord put together on this topic.

A number of excellent MSD resources from Peggy Hall (the “Head Mistress”):

Marine Sanitation: Fact vs Folklore
http://www.severnriveryachtclub.org/articles/sanitation.htm


Peggy Hall Speaks on cleaning the sides of Holding Tank
Live Aboard 0208: lv-ab: Peggy Hall Speaks on cleaning the sides of Holding Tank

Get Rid of Boat Odors: A Boat Owners Guide to Marine Sanitation Systems and Other Sources of Aggravation and Odor
Amazon.com: Get Rid of Boat Odors: A Boat Owners Guide to Marine Sanitation Systems and Other Sources of Aggravation and Odor: Books: Peggie Hall

And:

Marine Sanitation Devices ~ by Mark Parker
Good Old Boat: Marine Sanitation Devices by Mark Parker
__________________
Gord May
~~_/)_~~ (Gord & Maggie - s/v"Southbound")
"If you didn't have time/$ to do it right in the first place, when will you get the time/$ to fix it?"



I wont lie to ya, you are in for a hellish job.
Godspeed.
Erika

[Kettlewell]

I have done away with loops above the waterline in a system where the overboard seacocks were always closed and locked, except when pumping overboard offshore. It is a good idea to have your boat set up this way in the U.S. so that if you are ever inspected the overboard discharge is routinely closed and locked. I set up my system so that the head discharge always went into the holding tank. The holding tank could then be emptied via the deck fitting (pumpout station) or overboard via a pump if offshore. This eliminated one big through hull too.

[AllezCat]

Ok thanks for the replies.
It is a catamaran so not sure what you mean by healing
The top of the head is above the waterline, and it is freshwater so water inlet is no issue.
Just couldn't make sense of the discharges (one from the head system, and one from the holding tank system) looping, as they are not vented...
Does non vented prevent it from siphoning?
And can it be just a safety precaution if there are problems with the head, or tank units(which are below the waterline).
Would be real easy to cut the line as they pass the thru hulls and reconnect, rather than trying to thread them thru another space. (would eliminate 80 feet of hose too).
Will investigate route of vent first, may eliminate problem.
Previous owners had many toilet air-fresheners under the bunk. Reminded me of that scene from the movie "7"...
Will study those links

thanks

[AllezCat]

The vent terminates under the bridge deck.
So it is facing down towards the water.
And has several hills and valleys in the run...

[Boracay]

You need vented loops to prevent water from siphoning back into the toilet through worn valves. Joker valves may leak, even if in good condition.

I don't know your specific boat or head but is there any reason you cannot plumb the vent near your bunk to somewhere nice and high and distant from where you sleep? Having standing water in the vent line may not be a good idea. See next paragraph.

I've found that 1/2" vent hose can be unblocked by normal working pressure from my Lavac (don't ask...).

[AllezCat]

The 5/8 vent from the holding tank runs under the bunk too.
I have found the way to relocate (up-hill only) thru the same path as the pump-out hose. This terminates in the deck amidships - outboard. i think this will be ok - far from everyone.
The two 1 1/2" head hoses I will re-route the same way to the space under the bathroom vanity.

The above water line 1 1/2" discharge loops are not "vented loops".
Not sure if this matters/hinders/helps...
Would the vacuflush system be bothered by faulty joker valves as in a manual head?
But, this job is for next week, so can ponder...

[Opie91]

Originally Posted by Boracay

You need vented loops to prevent water from siphoning back into the toilet through worn valves. Joker valves may leak, even if in good condition.

I agree 100%. You should have a vented loop on every overboard discharge that has the possibility of siphoning back into the bilge. This includes bilge pumps(sometimes), raw water intakes and head overboard discharges. It adds and extra margin of safety.

This is an excerpt from a Don Casey Article:


Vented Loop
If your head is mounted below the waterline, or if it moves below when the boat heels, you must have a vented loop in a discharge line that connects to a through-hull fitting. Otherwise, if the head's internal valves are held open by debris-an inevitable occurrence-water will siphon back into the boat. Poor head installations sink boats every year.
Mount the vented loop so it will remain above the waterline at all heel angles. Clean the anti-siphon valve regularly to keep it functioning.



A vented loop in the inlet line can interfere with the proper functioning of the head, and its omission poses less risk because of the positive-action valve on the inlet side of the head. But if you leave the loop out, you must keep the inlet valve in good working order. A screen filter to exclude grass and other debris is highly recommended. If you want a vented loop on the inlet side, install it in the hose between the pump and the bowl.

Here is the link for the whole article:

Installing a Head by Don Casey

[cat man do]

Never had a vented loop on the last cat
Top of bowl was above waterline
ins and outs were (obviously) below waterline with PVC ballvalves

Turn on ballvalve to use
Turn off ballvalve when finished
Never had a problem

[CDunc]

Allezcat,
I realize a Cruising cat doesnt heel much but im sure when on a reach one hull sinks lower into the water than the other, whatever the waterline is when the hull is "down" would be the waterline + a few inches, I would use for positioning the vented loops.

[Wand]

Originally Posted by cat man do

Never had a vented loop on the last cat
Top of bowl was above waterline
ins and outs were (obviously) below waterline with PVC ballvalves

Turn on ballvalve to use
Turn off ballvalve when finished
Never had a problem

As cat man do says, you don't need all the extra plumbing if you just follow that simple two-step procedure. If, however, you have unreliable crew or guests, maybe the extra pipes and vents are a wise backup.

[Wand]

PS. A filter on the inlet side is also important...keeps the little living critters from entering the system and become trapped in the rim of the head, creating a smelly graveyard. Maybe it's just our waters but I've found the need for a filter on all raw water inlets.

[AllezCat]

thanks for the advise guys - very helpful.
I think the best idea/system someone mentioned is a holding tank mounted high - then open a valve and let gravity do the work.. In fact Chris White designs them so the valve mounted on the bottom is directly below the pump out line. So if there is a blockage it can be poked thru from above.
I remember seeing the Kontiki raft as a kid - they had a toilet seat strapped to the side. So easy back then...

But, that is not what I currently have.
I have uploaded a sketch of the current system.

Just to clarify.
This is a fresh water system. So there is no salt water intake and associated problems.
The waterline (even drastically healing) is at about the base of the toilet bowl.
When I mentioned vent line. I'm referring to the vent from the holding tank - 5/8". The two 1 1/2" discharge lines do not have a vented loop at the high point.

The vent requires relocation and an appropriate rising run without dips. This I will definitely do. It will pass thru the bathroom, instead of the bedroom and engine room. And exit on the deck adjacent to the pump out fitting.

The two 1 1/2" discharge lines loop under the bed. I can relocate to the bathroom. That would be better, and no different function.
But, I am trying to simplify if possible.
Are the loops necessary in the pump discharges of the vaccuflush unit and the holding tank unit?
There are no vented loops in the top point of the loop. Does that make them pointless for an antisyphining system?
They would provide a safety for flooding if there were catastrophic failure of the main components below deck. but not necessary for an above the waterline toilet bowl.

Closing the valves regularly is not an option.
BUT, neither of these lines are being used at the moment.
The holding tank discharge should be kept closed at all times, except when discharging overboard. So for safety of flooding, and not accidentally discharging, it should be constantly closed. So the loop and 20' of hose per hull can be eliminated.

The other should be kept closed at all times except when the holding tank is not being used. So, as someone mentioned, I could use the holding tank at all times. And pump out once per day or so when "in the bush". So I will eliminate that hose run too (and another 20' of hose per hull).

That would be a total of 80' of 1 1/2" head hose eliminated from under the bunks.

What do you guys think?
Does this seem practical?
thanks

[cal40john]

Yes the loops without vents are pointless as anti-siphon devices.

If the run of hose never goes above the waterline, then as soon as you open the seacock water will come in and fill the tank below the waterline. So the loops above the waterline even without vents are needed for that purpose.

The head being above the waterline is not a consideration, but your vacuflush tank and holding tank are below the waterline. They have ports, vents, fittings, whatever, if any of that leaks when you create a siphon those leaks will fill the boat. At least in the U.S. a survey for insurance or selling will probably point this out as a problem. They won't care if your usage pattern is safe by always closing the seacocks, the system must be installed as idiot proof as possible.

How old are the hoses? You have to replace them every 3-5 years as they permeate and the smell comes through the hose. With those length of runs I could start the great PVC debate again.

So if I understand your system correctly, with the vacuflush directed to overboard, there is something on the order of 40' of hose sitting in your boat with sewage sitting in it. How many flushes would it take to transport that out of the hose? Sounds like a very less than ideal situation from both the sedimentation and smell problems.

John