As you may or may not know, Lake Champlain has more stringent head
discharge rules that coastal waters, and requires that overboard
discharge points be physically disconnected. Closed and secured valves is not good enough. This same requirement applies in parts
adn the inland lakes of Maine
, and perhaps elsewhere, but I've picked Champlain as the example because the requirement is clear, and because the Vermont patrol inspects and fines if you don't comply.
My question is not about the rule
and whether it makes sense or is reasonable, but in techniques and mechanisms to comply. On my boat
, I have three points of discharge; two heads with Y valves that direct the flush overboard
or to the holding tank
, and an overboard pumpout.
Here are my thoughts so far, and I'm interested in how others have approached this:
- Simply disconnecting a hose is not acceptable to me. I don't want a boat
that can be flooded by someone subsequently opening a seacock, and I don't want an open hose that can discharge poop into the boat by some operator error.
- I could plug
the disconnected hose, and use a stub of hose and plug
to cap the seacock. This is easy, but not very reversible. Plugs are often difficult to remove, and the hose gets chewed up and eventually starts to leak. I could get comfortable doing this for the head
direct discharges since I never see a need to use them in any normal operation - flushing
into the holding tank
, then pumping out from there is fine. But the tank overboard needs to be easily disconnected and reconnected for travel between restricted and less restricted zones.
- The approach I like the most and am leaning towards is to use PVC or ABS flange couplers. These are mating flanges with a screw collar to hold the two halves together, and one flange face has a groove and o-ring in it. This approach gives a positive seal and can be opened and re-closed easily and with a positive seal. A second coupler with the openings plugged can be used to cap the hose ends when "disconnected".
- I've seen another device who's name escapes me that is similar in concept
, but uses threaded ends and a threaded coupler. One end is a reverse thread so you can screw both ends of the hose together by turning the coupler. Then there are caps to use when disconnected. My only hesitation with this is that the seal appears to be just a tapered pipe thread, and in my experience they are difficult to get sealed completely, and require a lot of pipe goop which makes for a messy fitting.
Then there are a bunch of related questions. Many people poo-poo (pun intended) the use of PVC or ABS anywhere below the water
line. These are schedule 40 and in one case schedule 80 fittings which in my experience are pretty darn tough.
I'm also wondering about where to place the disconnect within the physical limitation of the boat.
I'm thinking it should be above the water
line so there isn't captive seawater at the coupling when I need to disconnect it. But on the other hand, if it is below the water line there will be a washing
effect from seawater which would be desirable and disconnect time. Which is better?
I'm thinking the coupler should be on an uphill or downhill slope so it drains and won't be holding any surprises when opened. But should it be sloped towards the tank, or towards the water?