Mailport: February 2014
Joker Valve Search
I’ve been looking for a rubber duckbill valve for a vented loop in a holding tank system, and it seems Buck Algonquin (www.buckalgonquin.com) has the right fitting. (My understanding is that the words “joker valve” and “duckbill” are interchangeable.)
Nigel Calder, in his book “Boatowner’s Mechanical and Electrical Manual,” makes an important point when he says “A vented loop in the discharge line will allow foul odors into the boat. It is best to attach a small hose to the vent and run it overboard.”
Forespar (www.forespar.com) has a replacement duckbill cap assembly (MF-841) that does not vent overboard, and they offer a vent barb assembly (MF-846) that does not have a duckbill. It seems to me that you would want a duckbill in the loop so as to not clog the holding tank vent.
For an installation where you are pumping waste overboard, Buck Algonquin’s vent arrangement would seem to be the right choice. The joker valve part number is 60VL75CV; it is the one used in the Buck Algonquin 00VL75 assembly.
Let us know how it works. An alternative would be to simply place a check valve in thew vent line itself. They are cheap, easier to clean, and easy to service inline; we often flush them with a hose or compressed air, and sometimes use acid for cleaning. And yes, a “duck bill” and a “joker valve” are the same thing.
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