Okay, don't laugh... We recently got a larger sailboat that has a marine head rather than the Porta-Potti we were used to. Several weeks ago, we arrived at the marina to find that our boat was sinking! After a day of pumping out and clean-up, we determined that "someone" left the through-hull valve open and the Jabsco flush switch to the "wet" position. As a result, fresh water continued to siphon up through the head, filling the boat until the water level reached the waterline outside the hull. We now religiously close our thru-hulls before we leave the boat. My question is - do marine heads siphon like that, or is ours defective or installed incorrectly? The head is installed about 20" below the waterline (original design). Thanks!
- Status
- Not open for further replies.
P
Peggie Hall/HeadMistress
I'm not laughing...open head seacocks are the #1
cause of boats sinking in their slips. You're just very lucky that you got back to your boat when you did. Your toilet is not defective--although relying on the wet/dry valve to protect your boat instead of closing the seacocks is very high risk because those valves can fail in any toilet. The problem is in the installation of your toilet. Water is determined to seek its own level wherever it can, inside a boat as well as outside it. Your toilet is below the waterline. So without a vented loop well above the waterline in any hose connected to a below-waterline thru-hull, water WILL use that route to seek its own level inside the bowl via the toilet bowl or holding tank. The solution is to install a vented loop in the head intake. It should be at least 8-12" above the waterline at any angle of heel, and should be between the pump and the bowl...NOT between the thru-hull and the pump. The loop will not only create a 'hill' in the intake higher than the waterline, but also provide an air break to prevent the siphon started by priming the pump when you flush from continuing. However, a vented loop will not relieve you of your responsibility to close all seacocks when leaving the boat...it's only a backup-failsafe that will prevent the bowl from overflowing while you're aboard in the slip or on an anchor.
cause of boats sinking in their slips. You're just very lucky that you got back to your boat when you did. Your toilet is not defective--although relying on the wet/dry valve to protect your boat instead of closing the seacocks is very high risk because those valves can fail in any toilet. The problem is in the installation of your toilet. Water is determined to seek its own level wherever it can, inside a boat as well as outside it. Your toilet is below the waterline. So without a vented loop well above the waterline in any hose connected to a below-waterline thru-hull, water WILL use that route to seek its own level inside the bowl via the toilet bowl or holding tank. The solution is to install a vented loop in the head intake. It should be at least 8-12" above the waterline at any angle of heel, and should be between the pump and the bowl...NOT between the thru-hull and the pump. The loop will not only create a 'hill' in the intake higher than the waterline, but also provide an air break to prevent the siphon started by priming the pump when you flush from continuing. However, a vented loop will not relieve you of your responsibility to close all seacocks when leaving the boat...it's only a backup-failsafe that will prevent the bowl from overflowing while you're aboard in the slip or on an anchor.
E
Ed Schenck
A picture.
I, too, learned this from Peggy. The Related Link is a picture of my installation. The loop to the left is original, the one on the head to tank line. The vented-loop on the right is the new one on the water inlet side. It is a marelon material made by Forespar. You definitely want to do this. Select any of the head models on the Raritan site and you will see a good diagram of the installation. Or maybe that is what Peggy's link referred to.
I, too, learned this from Peggy. The Related Link is a picture of my installation. The loop to the left is original, the one on the head to tank line. The vented-loop on the right is the new one on the water inlet side. It is a marelon material made by Forespar. You definitely want to do this. Select any of the head models on the Raritan site and you will see a good diagram of the installation. Or maybe that is what Peggy's link referred to.
T
TXSailor
Thanks Peggy and Ed
I feel a little better knowing that my situation is not unique. I'll examine my Jabsco unit to see if I can retrofit a loop in between the pump and the bowl. I know that the waste line is installed that way (for obvious reasons), so maybe I can follow its path into the hanging locker behind the head. Thanks for the photo, Ed. Peggie you are an aqua goddess!
I feel a little better knowing that my situation is not unique. I'll examine my Jabsco unit to see if I can retrofit a loop in between the pump and the bowl. I know that the waste line is installed that way (for obvious reasons), so maybe I can follow its path into the hanging locker behind the head. Thanks for the photo, Ed. Peggie you are an aqua goddess!
T
Tom S
Peggy, are there any boat manufacturers
out there still not adding vented loops on the head intake? I understand this happening on older boats or owner installation, but I find it unimaginable that any boat builder would leave this out these days.
out there still not adding vented loops on the head intake? I understand this happening on older boats or owner installation, but I find it unimaginable that any boat builder would leave this out these days.
P
Peggie Hall/HeadMistress
Very few production builders install vented loops
If it's not included with the toilet, they won't spend the money for it. It's up to the owner to figure out that he needs one.
If it's not included with the toilet, they won't spend the money for it. It's up to the owner to figure out that he needs one.
C
Chris Burti
Catalina Does!
Although they didn't double clamp all of the below the waterline hoses on my 2001 320.
Although they didn't double clamp all of the below the waterline hoses on my 2001 320.
T
Tom S
Chris, I was going to say the same thing
My '99 Catalina 36 also has the vented loop. I'm not sure when Catalina started doing it but they've been doing it at least for the last 5 years. Chris - as far as double clamping, are you talking about the clamps on the Thru-hulls or on the head. The thru-hulls on my boat are double clamped, but I do agree, the raw water inlets on head is only single clamped. ps. I even think Catalina did a decent job on placing and installing the Head holding tank system (at least on the C36). The run from head to holding tank is very short and its a "downhill" run.
My '99 Catalina 36 also has the vented loop. I'm not sure when Catalina started doing it but they've been doing it at least for the last 5 years. Chris - as far as double clamping, are you talking about the clamps on the Thru-hulls or on the head. The thru-hulls on my boat are double clamped, but I do agree, the raw water inlets on head is only single clamped. ps. I even think Catalina did a decent job on placing and installing the Head holding tank system (at least on the C36). The run from head to holding tank is very short and its a "downhill" run.
C
Chris Burti
Ditto on the 320.
I've been wondering if the Electra San will fit where the holding tank is now. S'pose I'll have to measure sooner or later.
I've been wondering if the Electra San will fit where the holding tank is now. S'pose I'll have to measure sooner or later.
P
Peggie Hall/HeadMistress
Glad to hear it, 'cuz they didn't use to...
Now if they'd just stop running the tank vent into a rail stanchion... ALL hose connections--head, tank, y-valve(s)and other fittings, thru-hulls--in a sanitation system should be double clamped, with the screws on opposite sides of the hose. For two reasons: 1. The second clamp is a fail-safe. 2. Tightening a clamp can put a pucker in the hose under the screw that can leak...the second clamp seals any pucker created by the first one--which is also the reason why the screws should be on opposite sides of the hose. Some builders use sealant instead of a second clamp--or ANY clamp. This is a bad idea because a) sealant can leak, b) it may not prevent the hose from being worked off if the only clamp fails, and c) it makes it difficult if not impossible to take a connection apart if it ever becomes necessary. NO sealant of any kind should ever be used on a hose connection, only hose clamps.
Now if they'd just stop running the tank vent into a rail stanchion... ALL hose connections--head, tank, y-valve(s)and other fittings, thru-hulls--in a sanitation system should be double clamped, with the screws on opposite sides of the hose. For two reasons: 1. The second clamp is a fail-safe. 2. Tightening a clamp can put a pucker in the hose under the screw that can leak...the second clamp seals any pucker created by the first one--which is also the reason why the screws should be on opposite sides of the hose. Some builders use sealant instead of a second clamp--or ANY clamp. This is a bad idea because a) sealant can leak, b) it may not prevent the hose from being worked off if the only clamp fails, and c) it makes it difficult if not impossible to take a connection apart if it ever becomes necessary. NO sealant of any kind should ever be used on a hose connection, only hose clamps.
- Status
- Not open for further replies.