Just to add an experience I had doing this same thing a few years ago:
I had a 26' sailboat, that I obtained for "free". It needed a lot of
work (interior was near-gutted, etc), and the PO never informed me of an outstanding bill at the marina it was in. I was caught off-guard when I went to launch it to take it to my own. I would've still taken it either way, but it would've been nice to know ahead of time.
So to that point - any potential buyer that proactively asks questions in regards to
fees, bills, etc, is at least a step above a tire-kicker. It might not hurt to mention things like that in the ad, to at least limit some of the people that have no clue from replying. Some
marinas will allow for a slip transfer, others will require the new owner to pay something anyway. Your ad doesn't mention if it's currently in the
water, or waiting for launch, but it might be something to add. When I gave away my last boat a few years ago, I made sure to check with my Marina prior to selling, and they said they would just transfer the slip into the buyer's name for the remainder of the season. I signed the boat over to the new owner, with a retained signed copy of receipt, and also passed along his information to my marina, while he was to report in with them as well.
Frankly, I gave it away instead of selling, because to me it was a better option than ending up having to pay the
storage fee. I told the new owner I would give him the boat, so he could use what he was going to pay for the boat to pay for
storage, which let me unload the boat instantly and no longer have to worry about a bill myself. As you are at the beginning of the season, that might be a good selling point, if it applies - If you've already paid for the season and it's transferable, it could make it a lot easier for someone to use money they might have needed for the slip/mooring, for
repairs and justify
ownership.
Really though, the easiest way to weed out people is by the questions they do, or don't, ask. It should be somewhat obvious based on those as to their general knowledge or at least willingness to learn. (That's why I got a free boat for my first one, so I could use it to learn and build skills, so in many ways it was far more valuable to me than a
purchase price, and also why I scoff at the 'nothing more expensive than a free boat' schtick)
Looking at the boat, there's plenty of value to be had, even at the
price listed. If I were in the market, it would've been on the list quickly due to those factors. Hell, if I could afford two slips each season....lol