Practical Boat Owner (UK) this month reviewed bilge pumps. They liked the Vetus EB80 and Plastimo 1400 in the large size pumps as well as the Atwood Tsunami; all did about 45 liters/min at 1 meter of head, with 12v input. The Tsunami was rated well also for efficiency, ie...water moved per amp. The Rule 27D was mid-pack to upper mid-pack ib flow rate, head and efficiency.
The most interesting pump they reviewed was the new Whale Supersub 500 which only pumped 35 liters/min rated and 15 liters/min at 1 meter head tested but it's compact size and ability tyo fit in a narrow or shallow bilge impressed. Most impressive was that it drew just over 1 amp versus 3 amps and higher for the other pumps tested. It pulls water down to 12 mm and it sounds like it would be an excellent housekeeping pump.
Note that the numbers cited in their tests were at 12 volts, admittedly a low voltage situation.
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Wm. F. Buckley, Jr.