2Old2Soon, I have no direct experience with pulleys on docks, but I would say the pully system would have a greater dampening effect. For every one inch of dock movement up or down, the bucket on the pulley is going to move two inches. So it will take less weight with the pulley system to have the same effect as a simple weight hanging off the dock directly.
I could be wrong.
I learned about using a "snatch block" years ago from a winch truck guy I hung around. By using a dead weight (dead man) to anchor the dead end of the cable (the weight on the bottom of the pond in this instance) and a snatch block pulley (attached to the dock in this case)he was able to pull out much larger stuck loads with his modest size winch truck than by hooking directly to the tow. He had to pull in twice the cable length (would be the suspended bucket in this instance) but doubled his power at the snatch block pulley (the dock in this instance).
So by forcing double the movement at the bucket in relation to the dock movement, in which inertia of the weight plus the resistance of the water has to be overcame, the dampening effect would be much greater for a given weight.
At least that is the way I see it, but could be wrong.
