Originally Posted by bljones
Assuming you are docking bow-in: Your spring needs to be aft of your spinnaker padeye- for a springline to work properly as an "arrestor hook" when looped around the aft most dock cleat when docking, it has to be at, or aft of, the fattest part of the boat.
Enter slip slow, drop spring line over cleat, turn towards dock, throttle up, she'll snuggle right up to the dock- with a wind blowing off the dock, add more throttle after the spring is over the dock cleat.
I think this is correct.
If you attach your spring just to the stern, and power forward, the stern will certainly come in but the bow might start to pull away from the dock. If you attach your spring just to the bow, the bow will certainly come in and the stern will pull away. Someplace between these 2 extremes is a sweet spot that pulls the boat in parallel to the dock.
I'm also thinking that having the prop further forward via the sail drive impacts this balance point a bit, moving it a bit further aft...but not sure about this one.