Carver Mariner 350 (generation 2 1997-2002) Air conditioning manufacture.

[tomschauer]

Viper, it may be 10 minutes in Canada, but its about three hours in the Maryland summer sun to get the cabin below 80.

[Viper]

Actually summers up here can heat your cabin up to the hundred degree mark and higher under the right conditions, and it's definitely not a dry heat! I imagine it's likely worse in southern climes but three hours seems a long time to me for two and three air conditioners to bring the cabin temp down to 80* but it is what it is, I'm not disputing your experience. Maybe someone with more HVAC experience can chime in but is it unreasonable to think that 2 or 3 units should take much less than 3 hours to drop temps 20 to 40* in a confined space? I'm sure there are a lot of variables but maybe the real issue in such a case is balancing the system to the conditions rather than extended run times while minimizing short cycling.

In any case, 10 minutes or 3 hours, I wouldn't leave AC running unattended. A plumbing failure during that time could sink a boat. Too risky IMO. For me, the risk outweighs the amount of time I have to wait for the cabin to get to a bearable temp. I see plumbing failures all the time so no thanks.

[Midnightsun]

I leave mine on 24/7 all summer long otherwise it takes quite some time to cool things down. Cabin temps can easily get into the 100++ degrees with all the windows on these boats. Problem is everything on board is soaked to the bone in 100 degree heat and it's not a quick 20 min shot of cold air that will relieve the situation quickly. I do increase the thermostat to around 80 when we leave though.

[tomschauer]

It's often over 100 degrees and 80% humidity in the cabin on a summer Friday afternoon. Between that and the Chesapeake bay water temp (condenser water) being in the high 80's or 90 degrees, It takes some time to bring the cabin temp down. Its not just the confined space of the cabin, it is everything in the cabin, furniture, bedding, clothes etc. they all hold heat and need to be cooled. I have an 18,000 and 12,000 btu unit. They both run well at full capacity and have no issue holding at 70 when its 90+ outdoors.