These are the traditional mainstay of small craft bilge pumping systems and can offer surprisingly good flow rates, as well as a variety of installation options. Yacht racing rules state that at least one pump must be capable of being pumped from the cockpit with all hatches shut. The best way to accomplish this is with a through deck kit which allows the pump to be in stalled safely below decks while the operator pumps from above. A well designed manual bilge pump is very hard to block due to its large bore hose and valves and one piece diaphragm. The larger pumps in Jabsco’s line of manual bilge pumps are also suitable for ballast and waste transfer.