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From: Lew Hodgett (no email)
Date: Sat Sep 06 2003 - 20:11:53 EDT
Courtney Thomas writes:
>I'm not talking keeping the bilges dry but keeping the ocean out.
>
>what is commonly regarded as the best compromise given cost, size,
>power
>requirement, durability, and volume ?
You have to define "emergency".
I haven't done the calculation in a long time, so this may not be totally
up to snuf, but it's close.
A 2" dia hole, 12" below the water line will allow in excess of 60 GPM to
enter your boat. At 24" below the water line, the flow rate is about 100
GPM.
(If you are a techie, solving the "General Energy Equation" for the
conditions above will give you the exact answer.)
Under such conditions, getting the inflow reduced is the first order of
business. There lots of methods available, crash blankets, tapered plugs,
furniture, what ever is available, but get the flow reduced. Unless you
do, forget it.
After that, my choice would be at least a 2" NPT trash pump capable of
pumping around 200 GPM at at least 10-12 ft of head.
There is an outfit in Sweden that has a cute trash pump that mounts
around the prop shaft, if you have room.
After that, is an engine driven pump with a clutch.
None of the toy, Mickey Mouse pumps available from someplace like West
Marine are going to cut it.
SFWIW, my main bilge pump will be an 2" NPT Edson manual or equal.
Pump it every day as part of a normal inspection routine.
If I have to pump to often, or too long, it's time to investigate.
HTH
Lew
S/A: Challenge (Under Construction in the Southland)
There are no problems, only varying degrees of Challenging Opportunity.
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