All, I got a call from my wife Marilyn yesterday telling me that after a week aboard in the isthmus at Catalina Island with everything working perfectly on the boat, the Wilcox Crittenden Skipper II head up and stopped pulling sea water into the bowl for no good reason. We went through a bunch of diagnostics that I won't bore you with but what got it working again was "priming" the pump. It was made easier for her by means of the 3/4" bronze Groco vented loop I have mounted at chest height in the head. I had her remove the reinforced clear hose from the head side of the loop and fill it with water. She plugged it all back together again and now the head merrily pulls water since installing it several years ago. In case anyone is wondering what the vented loop does, it assures that the head will never siphon water into the boat and sink her. I have it mounted on the forward bulkhead, pretty darn close to the centerline of the boat over the keel and high enough that even on the most radical of heels, the loop never dips below the static waterline. In order to flush the head, the vent hole has to be covered with a finger tip before the pump will pull water. Beyond that, the head operates in the conventional manner and when uncovering the vent hole, the water in the intake hose side, returns to the static waterline. Crisis solved and all over the phone. Cheers, Glyn Judson, E31 hull #55, Marina del Rey CA