http://www.goodyearrvtires.com/pdfs/rv_inflation.pdf
You don't always inflate to max PSI. Depends on the load.
Your boat weighs 2123 dry. Add 800 to 1000 for your trailer and another 500 for gas and gear min. Probably at around 3500 or higher.
Going to have to bookmark that link! The very common, and very wrong, iboats knowledge is that you always, always, always inflate to what is on the side of the tire. That is wrong.
Tires are designed to have a specific sidewall angle and specific contact patch, which is achieved when the tire is loaded at the max weight at the specified PSI. If you are substantially lighter than the max weight, running at max psi will drastically reduce your contact patch. Iboats advice actually is making things less safe in this situation, not more.
(hint, watch the track of a bias ply tire when a trailer leaves the ramp empty vs loaded if you don't believe me...)
The other thing worth mentioning is that wheels have a maximum PSI also. Usually stamped on the metal and painted over, so generally tough to read. That is USUALLY well above the max tire psi for any tire you can fit on it, but not always. Never, ever, ever, go over the max wheel PSI.