Docking made simple:

1. Come in to the dock on a beam reach with enough distance between you and the dock to head up and "run out".
2. Come up pretty hard and make sure your sails tack over (allows you sail out away if you do not have enough momentum to reach the dock).
3. The distance traveled after coming up is dictated by how hard you come up and moving crew weigh forward and aft (too many times I've seen people rush forward to tie off to the dock and it kills their momentum - this may not be as big a factor on your trimaran, but is a big deal on lightweight cats).

Obviously, it gets harder the windier it is and the more crowded it is.