FWIW, the Marine
AC's I've been around all pull about 1 amp per 1,000 BTU of cooling
after starting as a rule
of thumb. Remember you have to include the water
I doubt seriously that 1 Honda
2000 will run a 15,000 BTU AC for expended periods, and as others have said, the poor little thing is tearing it's guts out trying. Remember it's a 13 amp generator at 100% duty cycle.
I have two Honda 2,000's and connected together they will run the entire boat, but two of them is twice the hassle, twice the weight and twice the size, not twice the fuel
burn though, two together will usually run it in ECO mode and that greatly reduces fuel consumption
One will run my front Stateroom's 5,000 BTU easily, if money
is an object, maybe you should look into trying a Home Depot window unit, they are very inexpensive for the cooling
capacity, but they are not as easy to integrate of course. A window unit is about the same size and weight as another Honda, but far cheaper.
I'm installing a NexGen 3.5 as the Honda's were too much of a hassle.