T&T: Raw water washdown...

[Peter Bennett]

Friday, May 15, 2009, 10:40:57 AM, Marin wrote:

FM> A previous owner of our boat installed a large Jabsco AC powered pump
FM> (this pump is still available as the Jabsco Model  6050) that uses a 3/4
FM> hp Westinghouse AC motor to drive a large bronze pump.  The spec sheet
FM> in the manuals folder on the boat says it has a max volume of 23 gpm.
FM> It has a Square-D pressure valve plumbed to it to shut off the pump
FM> whenever the trigger on the spray nozzle is released.

FM> But....... it's AC and it draws a lot of current.  We have an inverter
FM> that will power the pump but that means we would have two heavy loads on
FM> the batteries/alternators at the same time--- the anchor windlass and
FM> the pump--- and combined they will draw much more than the two 45 amp
FM> alternators can put out.  So we start the generator when we're going to
FM> haul up the anchor and use that to provide the AC for the washdown pump.
FM> The pump has its own seacock which we keep closed unless we're actually
FM> going to use the pump.  The plumbing runs to the deck spigots at the bow
FM> and stern is made with very heavy hose.

Although the windlass and pump/inverter both draw a significant
current, they do so for a short time, so the actual ampere-hours used
is really quite small.

I think my windlass has an 80 amp breaker - suppose it really draws 60
amps, and takes three minutes to get the anchor up - that is 180
amp-minutes, or 3 amp-hours.  Probably insignificant compared to your
total daily draw.  The batteries can easily handle that, and the
alternators have your whole day's trip to replenish things.

FM> ______________________________
FM> C. Marin Faure
FM> GB36-403 "La Perouse"
FM> Bellingham, Washington
FM> _______________________________________________

-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Ennos 31 "Honeycomb"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca