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Most small boats have these. Even boats with electric bilge pumps often
have hand operated Bilge Pumps for emergencies, and lifeboats have them
too. |
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A flapper valve (rubber disk) at the base of the pump keeps water from
falling out when the handle is depressed. |
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At the same time, a sliding disk valve at the bottom of the traveling piston,
is forced open by water pressure allowing water to enter the upper part
of the cylinder. |
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On the upstroke the disk valve on the piston is forced closed (down) and
water is forced up and out the top. At the same time the flapper valve
opens and the decreased pressure in the lower part of the cylinder sucks
water in from the bilge. |
