We are sailing a 42' yacht in southwest Florida
. Our AC is a 16,000 BTU unit made by KingAir that is mounted in the salon/main cabin. It is not ducted to the fore or aft cabins. Instead, small fans move the air around quite nicely and keep the boat very comfortable quite easily (sometimes too cold at night). The cooling
water is picked up under the gally sink and passes through a Perko raw water
filter that is easily reached/cleaned. Condensate is drained to our bilge sump. One thing we did that is a departure from the routine is to require two drains in the condensate pan, one each on the port and starboard sides to ensure that, no matter how the yacht heels, the condensate that remains in the pan even after the system is shut down can drain rather than overflowing onto the decks. We tried one of the venturi devices, a "Condensator", for a year or two but found it very problemsom, requiring constant maintenance
and replacment check-valves (it got to the point that I would buy 10 at a time from US Plastics at a buck each). We finally did away with the thing entirely.
Our pump is a March MDX. These work well and are designed for dry operation. Maintnenance involves injecting a little 3-in-1 Oil
in the oiling galleries every few months. The pump activates whenever the compressor
comes on, wither for cooling or heating
(in the winter). While there might be only a single water pick-up, I would suggest independant pumps for each unit if you elect to go with two, although I don't think that's really necessary (different ships different long-splices however).
It is wise to set your system up with access ports
in the cooling water lines so that you can periodically backflow the heat exchanger
to clear our debris and run a descaler solution through the system from time to time.