jsimon wrote:
I put together a crude drawing of how I tie up as to not have to use fenders at the marina, and bump into the dock all night.
It'd certainly work on a floating dock. And it'd likely never be a problem unless you got into at least 4' or more tidal change.
You always want things tied such that you never end up with the boat's weight 'hanging' from the cleats. I use variation of that setup. I cross the stern lines. I also run my spring line from the port rear cleat forward to a piling on the port side finger pier. The crossed stern lines give a 'scissors action' to the rise and fall of the boat during tidal changes. This allows the boat to move forward and backward slightly in the slip. Tying 'directly' like in your diagram doesn't leave quite as much room for movement.
I also use a couple of rubber line snubbers on the bow lines. These keep the lines relatively taut in normal situations while leaving about another 2' of stretch for extreme tides. We get occasional 'blow out tides' that can drop the tide as much as 3' lower than usual. It doesn't happen often. But the snubbers save me from having to make a special trip to the boat to readjust the lines.
What's also different is I don't have a lot of clearance on my width. There's really no more than about 12" of room on either side. So I have to make sure to have enough forward/backward movement without much side to side. This is why my port side spring line needs to have a cover over it to prevent chafing against the hull. I could avoid this by using a spring line from the port side amidships and then to a pole off the bow. But this would mean having a much longer line left on the port bow piling. It'd naturally fall in the water too often and end up getting slimy, which would make for more cleanup work for me.