Sizing an A/C for a Catalina 30

[OS2Dude]

We just bought a 1985 Catalina 30. My wife's condition demands she not get overheated, so we are thinking of installing a marine air unit. After speaking to several 'knowledgeable' people, no one can tell us what size we should look at.

The wife will need it to be in the low 70's/upper 60's during the day. (Currently in Lake Sidney Lanier, Atlanta GA, but may head to FL in a few years.)

I take it that you don't want too much BTU for the same reasons you don't over power a home. But we don't want to go to the trouble and expense for a unit that is too small either.

We're planning on giving up some or all of the starboard side water tank for it. Initially it will be shore powered, but eventually would like to add a small genset as well.

Any ideas on this? What about brand? We currently have a CruiseAire unit that is being loaned to us. It helps, but I don't think it will cut the mustard once summer gets into full swing.

(FANTASY: Replace diesel with electric motor and run A/C and propulsion off genset. Locate genset were diesel is now, or possibly take part of quarter berth under cockpit for it.)

 

[boblufkin]

I added the portable one that dropped into the forward hatch -,4500btu took the edge off.

For a built in one I would go for 8000 btu. You really don't have much glass.

 

[leghyker]

I would go with at minimum 12,000 btu unit. Myself I would go with a 16,000 btu unit. That's what I have on my 36 and it does fine in Florida. You can't make the boat cooler once you max the AC unit out. But you can make it warmer to keep the AC from short cycling.

 

[Stu Jackson]

There are sizing guidelines based on the volume you need to cool. Do some internet research. Like, Google "sizing air conditioning for sailboats." Good luck, that's what I'd do if I wanted to find the answer that was right for me.