I had a bilge pump teed into the sink drain. The T was actually below water level and it loopep up just above water level. Well.......after a new engine install and some new wires and hoses, it got pushed to just BELOW water level. We woke up in Rock Hall about knee deep in water! After pumping the boat out, we were like WTF??? where did this come from?? We listend very carefully and I heard water running back into the bilge through the pump. That pump now dishcharges out of a hull fitting up at rail level ;) Note the T setup caused no issues for at least a decade or so prior to this.
Joe Della Barba Coquina C&C 35 MK I -----Original Message----- From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Kim Brown Sent: Tuesday, August 13, 2013 7:34 AM To: cnc-list@cnc-list.com Subject: Stus-List Bilge pump siphon Steven, Had a similar problem with my Irwin 31 - there the bilge pump discharge was tee'd into the sink drain. All is good unless you had a stopper in the sink then there is no break in the line and a back siphon could set up. Then the pump (hopefully) kicks in and pumps it out and then it back siphons again ad infinitum. Took some panic time to figure this out when I came back to the boat after a night on Duval St. Admittedly my thinking was impaired.... With the stopper out the siphon couldn't set up. Solution was to stop doing dishes..... While high loops are good. you need something to break the siphon - discharge above the waterline does it; check valve will do it but I would look at a siphon break like they use for heads to be inserted at the top of a high loop- less worry about impeding any discharge. And good practice is to 'cross' hoses. If it runs along port, loop up in the stern and discharge it to starboard and vice versa that way if you actually are doing something like sailing one side or the other will be high. Kim Brown Trust ME!!! 35-3 -------- Original message -------- From: Steven Winks <swi...@cogeco.ca> Date: 08/12/2013 9:15 PM (GMT-05:00) To: cnc-list@cnc-list.com Subject: Stus-List Bilge pump siphon Hi. I have a 34+ and had an unusual thing happen this morning while at anchor. I woke to the sound of my electric bilge pump cycling on and off. The bilge was full of water. I turned the pump on to drain the bilge and it filled up again once the switch was selected?to off. I had the same result with the manual pump. When I removed the manual bilge pump hose from the bilge and then turned on the electric pump again, the bilge stayed dry, so the water must have syphoned in via the manual pump discharge. The discharge on this boat lies only a few inches above the waterline, but with any weight aft, it is below the water. Has anyone else experienced this? I understand check valves are not recommended. Thanks for any advice. _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
