My current slip is over-sized for me (a 40 foot slip for a 33 ft boat) and too much room can be just as bad as too little. but I manage nicely. The boat next to me, however, is a Beneteau 393. Its beam barely fits into the slip, which is an increasing problem with older marinas here on the Chesapeake and the newer designs with much more beam than in the past. My neighbors probably have 6 inches on each side, and this is not on floating docks either. They manage but have to put out about a dozen
fenders to protect the boat. Even then if there's a hard wind or extra high or low water the
fenders can get out of position and the boat rail will rub. I have adjusted the
fenders for them many times when I have gone down to the marina and they aren't there.
The good news for them is that when they return to the slip after an outing, they can more or less jam the boat into the slip. With the fingerpier on one side, pilings mid-ship and at the bow, once in they aren't going to blow around much. Fortunately the rubrail on the Bene is just big enough to protect the boat until they can get the
fenders into place. They also have put protection of the pilings and the fingerpier, which helps protect the boat as well.
Alas, I am moving to a 35 foot slip on the other side of the marina this coming season so they will have to find a new nieghbor to look out for their boat.