Air conditioning

[Andrew-Calliope]

I'm thinking of installing air conditioning in my Broom 42 motor boat but we only have a small (3kva) generator so the maximum we can run is 16,000 Btu. We're currently in the South of France but are heading towards Greece next summer where it will be hot. Will 16,000 Btu make much difference? On my previous 47ft catamaran I had 50,000 Btu but that was in the Tropics

[Coolerking]

What are the dimensions of the area that you will be installing it?
Are there lots of glass windows that are directly heated by the sun?
Its all about how much heat the boat ingests from the sun and the engines and the electrical systems, if you are clear of that then you will be fine.
If its a large area and has a high heat load then you most likley will not have an "ice box" per say, but it will make a huge difference in your quality of life onboard.

[skipmac]

Depends on whether you want to be nice and cool or just want to kill the heat and humidity. Also depends on how much of the boat you want to cool.



I have 16 kBTU on my 42' sailboat and it will keep the aft cabin nice and cool, the main cabin good and the forepeak tolerable. Of course a 42' power boat will be have about 50% more interior space than the sailboat.

[a64pilot]

It really doesn’t matter much, he can only run 16K. So 16K is it.

However he may be the case if you will that the new inverter air conditioners is made for, they are apparently much more efficient and he may therefore be able to run two air conditioners, or run one at a much lower generator load.

[Andrew-Calliope]

Not necessarily - if it's not going to make much difference then I won't install it. I've looked into the "new" units using DC brushless motors but the energy saving doesn't appear to be hug. The main advantage is in low start-up power. They are quieter, but if using the generator, that won't help much.

[GordMay]

A rough "rule of thumb" for sizing marine air-conditioning (for use in sub-tropics) is between 14 BTU/H (below decks) to 17 BTU/H (above decks, glazed) for each cubic foot of interior conditioned volume (living space).
A professional will size the air conditioner based on the latent cooling load (which considers the relative humidity of the air), as well as the sensible cooling load (which considers the outdoor & indoor design air temperatures) for your boat & location.
A (theoretically) perfectly-sized air conditioner will run continuously during the hottest 2.5% summer design (outdoor) temperatures.

[Pete7]

I think you are going to need some sun shades as well, problem is a yacht as lots of sticky up bits to support them, bit more tricky on a mobo.

What colour is the bimini/sprayhood? we are thinking of replacing our navy blue one and whilst very smart in dark blue when new, you can feel the heat on the underside even in the UK. Wifey and I just can't decide on the best colour, she wants light blue and I want a light grey. So bit of a stalemate at the moment, not helped that she is paying for it.

Pete