In a full facility marina, I would put the water heater at the bottom of the priority list. If funds are limited, rebuild your existing head- new hoses, new joker valve, some enzymes flushed through the system. (BTW, when you buy the head parts, invest in a jar of vicks vap-o-rub. Rub some on your upper lip before you start working on the hoses. Trust me.)
Buy a barbecue before you buy a stove. Cheaper and more useful for bachelor cooking. Since you have shorepower, buy a microwave before you buy a stove, for the same reason.
If your war chest is limited, buy a GOOD sewing machine, and the Don Casey library. That will take care of the bimini, dodger, cushions, etc. and most of the other jobs you might be tempted to pay somebody else to do.