Originally Posted by bony
The tidal range at my location has an average of about 8' or 2.4 metres. Most of the boats there seem to allow a fair bit of slack although there are some fairly haphazard setups. I'll have a talk to a some boaties down there to see if I can get a few pointers.
With the range you mentioned I would use blocks and weights. Affix a block to each corner tie-point, and run 10mm nylon line through. Each corner line should be long enough to reach from the opposite side of your boat to the block, plus enough length to accomodate the maximum tide range plus knots at each end. Attach 10-15 kilos weight to each, and tie all corners to a central line that is longer than the length of your boat. The central line will be your grab-line when you enter the slip, and you will use it to bring each corner line to a cleat on your boat. it will lie along the deck slack when your boat is tied in it's slip.
This will keep your boat centered in it's slip, and allow easy tie up when you enter.
This is the way they do it at the small boat docks in my harbor. If you need further clarification let me know. I might be able to take a picture later.
PS - you might need more weight if you have high winds. The people around here use scrap metal and discarded dumbbell weights.