"Peggie Hall" wrote in message
. net...
Garland Gray II wrote:
Actually, at the time I didn't know better, so I did not install a
vented loop. I'm sure I thought you couldn't put one on the intake
side. (This was a catamaran, so heeling didn't make the risk
greater. ) Now that I think about it, the survey (it was a 6 month
old demonstrator boat) didn't make mention of this deficiency.

If the toilet is completely above the waterline, it wasn't.


It was almost completely below waterline.




But let me ask you about a related "theory" I have. My old boat w/o a
vented loop had very little odor from the raw water after the head
had not been used for a week or two or more. Only briefly after the
first flush. My present boat w/ a vented loop has a much stronger
odor from the raw water for many flushes. The longer raw water line
because of the way the vented loop is run must affect this, but I
wonder if the contact with air in the vented loop doesn't cause a
greater odor problem ?

The longer head intake line is likely to be the cause, because the longer
the line, the more sea water is left in it to sit and stagnate. But the
vented loop has nothing to do with it. For one thing, it doesn't passively
allow any air into the line, it only pulls air into a line through which
water is actively being pulled. But even if it did, adding air (oxygen)
would reduce odor, not increase it...'cuz the more aerobic the conditions,
the less odor can be produced.


I expect that the water between the vented loop and the bowl that is higher
than the top of the bowl eventually drains to the bowl, to be replaced by
air. But I'll trust your knowledge of bacteria.



However, if the vented loop is in the intake line between the thru-hull
and the pump, it is likely to create another problem: interfere with the
pump's ability to prime by introducing air into the line that the pump is
trying to start by priming. It needs to be between the pump and the bowl
where it can't interfere with toilet flushing because flush water is being
pushed, not pulled, from the pump to the bowl.
--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://www.seaworthy.com/store/custo...0&cat=6&page=1
http://shop.sailboatowners.com/books...ku=90&cat=1304