Per the rather highly detailed drawings we provided for Boojum (sheets # 18 & 26 out of sheets 34 total...!) all bilge discharge lines were designed with high loops to prevent backflow. The bilge discharge line high loops were designed to reach the highest available spot locally: i. e. just beneath the galley counter top, port side. If those drawings were not followed during construction, it is the result of inattention (or very possibly disbelief re: the available space in that location) on the part of the builder. It is possible that, given the size of Boojum (25 feet) that even if the high loops were taken right to the under side of the galley counter top, that water could still slosh over the top... a vertical distance of 3 feet above the DWL. This question can be best answered by Charles via inspection of the lines below the counter top, to see if they were taken to the intended height... Regardless of whether a drawing detail exists to specify a high loop in a bilge line, it should always be assumed to be the case by the builder. The additional use of a non-return valve can be desirable in some cases in order to prevent "cycling" the bilge pump when the high loop is long enough to allow sufficient water to return to the compartment to cause the pump float switch to turn the pump on again... an endless cycle that can be prevented by using a check valve at the pump. PS - I do not subscribe to the TWL list. Anyone sending a reply intended for me should please send it directly as below. Best regards, Michael Kasten michael@kastenmarine.com http://www.kastenmarine.com ______________________________ ----- Original Message ----- From: "Michael Schooley" <schooley@keyway.net> Subject: FW: TWL: Boojum back in Opua Hi Michael; I know you are busy, but I thought you might be interested in this question about Boojum's bilge pump pluming. Maybe you have already seen it. We had a water leak during a recent vacation, ..............snip Happy Holidays; Mike & Ruth Schooley