Join Date: Jul 2002
Thanked 4 Times in 4 Posts
Rep Power: 14
Ken, I concur that the computations are way off. Your boat should be using a 12,000 or 16,500 BTU unit depending on several variables.
FWIW as a benchmark, our 42'' x 13'' Pearson 424 has a 16,500 reverse cycle unit and is used when we''re in the Tampa Bay area. We also used it for a summer (storm) season in Trinidad. Both these locations put a high demand on the unit, which is frankly marginal in capacity for such volume and heat. However, we use awnings when dockside in hot weather and find it makes it possible for the unit to maintain an average 80 degree temp with cycling about 60% daytime and far less at night (ambient of an average 90 daytime, 80 night). Hopefully, that data point will help you a bit.
Your unit''s performance will depend on use of awnings, ambient conditions, amount of boat insulation, injection temp (or temp of water in which boat is sitting) and other variables (how willing the crew is to listen to the unit running; how frequently you are coming & going, admiting hot/humid air, etc.).
And FWIW, our unit is a rotary Mermaid Marine unit that''s now 6+ years old. The folks are terrific to work with, we just did a total refurb on the unit at their factory (we''re nearby) where we learned that the cause of our eventual freon loss (metal condensing coil which rusted out) has been replaced by a copper coil 1/3 the size but with more efficiency. The refurb cost us 1 day ''layover'' at the factory and $165, terrific value for a unit that now looks brand new. But the folks running the business (it recently changed hands) are super, even better than the previous owners tho'' I thought that would be impossible.