Recommended Floating Dock Slip Width

19' which will give you enough room to put fenders on both sides, but the wider the better.

Really all depends on the weather and tidal conditions of the marina. I use a slip somewhere that is perhaps 20+ feet wide with an 18.6 beam. Waters are dead still and tidal current is nominal in terms of impact. It's also well protected from winds in passing storms. I deflate my fenders to use them on each side.

Fendering can be installed on the dock and would only intrude 2" on each side. So depending on how good a boat handler you are you can get by with less than 17'.

What are you going to do with the extra 1 1/2'. Seriously all you need do is get one corner in and you're home. They sell wheels that you can install on the corners to make it easier for you. https://www.westmarine.com/buy/tayl...ble-dock-wheels--P005_157_006_507?recordNum=1

If it's your permanent slip and you can put those rubber wheels on the outside corners and permanent fenders on the dock all of the way in you would be ok once you get 10' of the stern in and start backing in. Not fun in all conditions, but do-able.

This. Your beam at your water line is typically less than the widest section of your boat at the cap rail. The really big question is tidal and wind conditions coupled with your confidence in maneuvering your own vessel. As has been posted, getting one corner of your stern clear is as good as being home, especially if you're twin engine, and a thruster makes it a no brainer. But visit your favorite place a few times on the tide clock and watch the behavior of other boats and the signs of current. Understand what you're going to be contending with on most occasion.

As I said, I'm in a slip for a season each year that I wouldn't be in if the tide or wind was much of a concern, but they aren't big factors, and I literally have less than one foot on each side. Once I'm in I deflate me fenders and use them partially inflated to fend the boat in my absence. I don't have a corner roller to use, but I would employ one if the tide movement brought challenges.

When I taught my ideal situation was on our south shore barrier islands during the week when there'd be plenty of empty slips. I'd drill my students going in one slip then flip around and go in the opposite slip so they'd get the wind / current on both sides. Worked with one fellow about April. He did good. Got a call from him after July 4th for another lesson. Said when he went to Fire Is. he hit everyone. I asked when he had the boat out last before this. Not since our lesson. I explained that he could hire me every time he takes his boat out $$$$ or he can practice.