My .03 for you ...........
I run in Long Island Sound, the Hudson River and the Atlantic all the time with my 16s. If you want a 16 I would strongly suggest you get a later year Sweet 16 with two forward facing bucket seats if you're going to explore with it. The Sound and the various Bays can get going and two buckets make the 16 a lot more family and rider friendly and still give you the great looks we all love.
Second thing is as pipnit said, look for a fresh water boat instead. I boat exclusively in salt water and you are always going to have surprises when you buy a salt water boat. You would limit those if you spend a few more bucks out of the gate and get one that is fresh water only. The 16s are small enough that you can expand you search area to include places like New Hampshire etc and just go drag it back behind the car. There are a fair amount of 16 I/Os coming on the market now so you should have some choices.
Third thing, if you decide to go older have a pressure test done to check the gas tank.
If you find one people here would be glad to put a quick set of eyes on it before you have to travel any distance. Good Luck!
1972 16 OB - C16B-63 - "Surface Tension" Resto Project
1974 16 OB - DMR16106017-B - "The Mule"