Would it hurt anything to close off one of the outlets to run more air into the salon?
No, but it may not do much good. The air in a 28 ft boat spreads easily and sending more to the saloon
may not really change anything. While the air temperature being hot is one thing the other part is the water
temp. The hull
becomes the temperature of the water
. Add a really hot day most boats will need to push the BTU's to stay ahead late in the afternoon.
Make an awning that covers the deck
. It can get you back 10 degrees. It's that or tie up in the shade. If you can find a marina in the shade I could move there too. This summer really has been a rough one. My upstairs in my house has trouble. With dew points close to 80 and heat near 100 degrees.