On 17-Oct-2003, wpatrick wrote:

Can any of you make a recommendation for an electric bilge pump to use in
our Prijon Kodiak and Seayak boats? They are plastic boats with foam
bulkheads.

I prefer Atwood pumps. They are conservatively rated and perform well.
The competition tends to overrate their pumps. The following table
(use fixed font) shows the time (in minutes) required to pump 100 liters
of water. Data taken from manufacturers' web sites a couple of years ago.

Pump 12V G/Hr liters/min Lift Drop Time Amps
Rated Reduce 10%
Whale 300 420 26.5 23.8 4.2 1.9
Rule 500 480 30.2 27.2 3.7 1.9
Whale 500 502 31.6 28.5 3.5 2.3
Attwood 625 650 41.0 36.9 2.7 1.2*
Rule 800 700 44.1 39.7 2.5 2.8
Rule 1100 1050 66.2 59.5 1.7 3.3

* I measured this at 0.9A in my kayak.

Note that with the Attwood 625, at 0.9A current - the lowest draw,
you get the third greatest pumping capacity. Since battery
capacity is directly related to the current demand, this allows
you to put together a pumping system with the smallest battery.
The 625 is actually better than the Attwood 500 - more capacity
for the same or lower current.

In fact, a dozen 1.2V AA NiMH batteries in series (14.4V) will
adequately power the Attwood. This would be lighter and easier
to deal with than AGM or other sealed lead acid batteries or
even NiCd. Just make sure all 12 batteries are the same type
exactly (e.g. all 1800 mAh) and make sure they are always charged
to the same level.

You can do a search on pump types. The following was one article
I looked at when researching my pump.

http://www.powerboat-reports.com/sample/bilge.html

Mike