Yes, but. It's all a matter of sizing, as big ships do it all the time and
I really prefer having only one intake seacock -- when we bought Swee****er
she had ten. Aside from cutting down on intakes, it allows you to put the
seawater intake on one side of the keel and the head discharges on the other
(ours were LectraSan treated, but at sea it has to get overboard even from a
holding tank).

We did this without problems with a 2" seacock on Swee****er. The main was
a Yanmar 4JH2-DTE (75hp) and we had no problem with starving any of the
smaller devices (3 air conditioners on one March pump, 5kw genset, 2 manual
heads, refrigeration condensers (220VAC -- March pump), watermaker, and
galley foot pump). The March pumps did give trouble in trade winds
conditions when there was a lot of air under the boat, but that was with the
engine off.

Glenn's 1.5" seacock is only roughly half the capacity of a 2", so I might
worry a little about it, but my guess is it's OK.


--
Jim Woodward
www.mvFintry.com


"Michael Porter" wrote in message
...
I'd second Evan's condern. I was on a boat once which had a head
feeding off the same intake as the genset. In a short time, the
genset dried out the head valves and pump and made them useless.
Replacement of the valves and pump leather and a check valve helped,
but you still couldn't flush the head with the genset running.

Michael Porter



"Evan Gatehouse" wrote:

snip

I don't think ABYC cares too much of what is downstream of the seacock.
Figure it out this way, if one of your PVC valves fail, it won't sink the
boat because you can close the seacock easily. You could also use
Marelon
if you're worried about the strength of the PVC valves.

The only thing that worries me about all this manifold is the engine pump
starving the R.O. or AC pump because it sucks harder. On commercial
ships,
the seachest is big enough to deal with this issue, but if I'm reading
you
correctly, a single 2" intake is supplying everything?

Michael Porter Naval Architect / Boatbuilder
mporter at mp-marine dot com
www.mp-marine.com