"MarshallE" wrote in
:

I am told that some boat owners use a residential style of heat pump
with great success. Any thoughts?

Some of them use window air conditioners on the deck. Is that what you
mean?

What brands are best for marine grade? Is this a project that the
average boat owner can handle?

"Marine Grade" just means it came from a marine store at 10 times the
price. Marine AC units use the same compressors and electrical
connections as any other refridgeration units. It's mostly bull****,
except marine installations INSIST on putting the hot electric fan motor
and really hot compressor INSIDE the air conditioned space where it will
make the most noise all the time, keeping you awake, and create the most
inefficient air conditioning system in the process because the unit
expends a LOT of its Btu capacity cooling ITSELF, pumping its OWN heat
out of the boat before it can pump your heat out of the boat.

Stupid, isn't it?

Any boat owner who can do basic electrical wiring and rubber hose
plumbing, which I figure is about 30% of the owners in any marina, maybe
less where the lawyers park their big yachts, can accomplish. Testing is
easy. Hand them a two cell flashlight, two D cell batteries and a
flashlight bulb. Tell them to make it light.

The only thing you really have to concern yourself with is:

1) Electrical wiring to the AC panel, preferably to the NEC would be
nice, but not necessary.

2) Installation of a seawater electric pump, strainer, and hooking them
up to an underwater through-hull source of seawater, preferably not
shared with anything else in the boat, low enough so the damned thing
will SELF PRIME without tearing the hoses apart to prime it under the V-
berth every time you come home from sailing heeled over so that fitting
comes out of the water and it all drains out letting air
in....grrr...nuts.

3) Plumbing in flexible duct work INSULATED so it doesn't sweat inside
the cabinets it passes through rotting all the wood inside the cabinets
to hell a couple of years from now. The cabinet the AC unit sits in will
be like a swamp because it constantly drips condensate water, just like
at home only 5 times as much in the sea air. That cabinet is like a
swamp as soon as you shut it down and the stagnant water in the drain pan
that never drains right makes it like a swamp in there as the hot fan
motor and hot, hot compressor raise the cabinet temperature after
shutdown to 150F for a couple of hours....(c;


The cost to go with a residential is much less but I am concerned that
the marine products would be better.

I have a terrible time convincing them, but the BEST solution I ever
installed was a nice Coleman 18000 Btu RV rooftop HEAT PUMP over the main
cabin hatch with the Coleman Easy Start Kit already installed. All the
noise from the AC, the noisy compressor, the noisy fan motor, the
condensate swamp water and everything except the small inside control
panel and distribution outlets fore and aft that stick down in the cabin
about 2 inches is OUTSIDE WHERE YOU'RE SLEEPING! Even the smallest RV
unit will make a boat MUCH colder, MUCH quicker than a "marine grade"
unit twice its capacity. You'll freeze your ass if you turn it wide
open...(c; The "Easy Start Kit", not available on "marine grade" units
I've ever seen, starts the compressor SLOWLY, without the 30A starting
surge current every time the compressor comes on. This allows you to run
the little rooftop unit with a PORTABLE or SMALL INBOARD generator! How
cool that is anchored up a creek on a hot, sweltering night full of
Florida mosquitoes the Manatees are afraid to surface under!

One of our old neighbors had a 40' catamaran sloop. He nearly died while
trying to figure out how and where to put a Marine Air that still left
room for a few cans of food and a plate or two in one of his
pontoons....er, ah, belay that, I'm supposed to call them "hulls", not
pontoons. He asked me what I thought and I put the Coleman buzz in his
ear over that really nice skylight hatch that was just sitting there
cooking anyone in the sunlight that sat under its cheap, clear-plastic
cover.

He tried it.

He like to froze to death the first night as he forgot to turn the
thermostat down and woke up at 2AM to a boat only 47F internal
temperature...(c;

If you think it looks just awful sitting there on the deck, have your
custom canvas shop make an anchor or ship's wheel logo cover for it
that's padded on top. Ignoring the snobs' comments about it being a
trailer air conditioner, after seeing them cursing those biting little
centipedes that filled up their sea strainers causing THEIR professional
"marine-grade" AC to overpressure and trip out 3 days ago, and tell them
it's a "custom made deck seat" with ship's wheel upholstery....(c;

Oh, get the model that you can control the airflow out each of the outlet
ports individually. That way you can force more air one way where
there's more heat and not into the V-berth freezing her you-know-what
during sex...not a good thing.

PERMANENTLY MOUNTED with the included hardware, that makes it MUCH better
than those damned portable marine units you have to lug around every time
the boat moves.

Look on top of the tugboats and trawlers! They use them because they
WORK.

The whole thing costs just a little more than the seawater pump in the
"marine grade" thing in the closet. So, when it finally rusts out...you
just BUY A WHOLE NEW ONE. It takes YEARS on a shrimp boat with NO
MAINTENANCE WHATSOEVER....