For the hot humid FL summer I installed a $160 Walmart room AC of 6000 btus. We have a 39'
steel boat with 2"
insulation to the
water line. It will knock 20 degrees off the outside air. We mount it over our 24' square
deck hatch with a 3/8
plywood baseplate and 2 down ramps, one for
cooling and a slightly smaller one for the return air.. It also helps to suspend a
water proof cover over it to deflect the rain over it and it also helps cool the unit. Make sure if you use Walmart that you check the customer
reviews. Our store carried a 5000 btu unit that was rated poor by most if not all purchasers. We had them order the 6000btu unit in for use and explained to the store manager that they should carry this unit over the crappy 5000 btu unit ( $20 difference in price). COOL hanging out at the marina in the summer that way.