Okay, obviously NOT under sail.
Going (sailing) backwards at a high rate of speed, either by motor or tug/tow. Why is it going backwards if not being towed into position?
From the fact that she is NOT under sail, is traveling BACKWARDS at a high rate of speed, and old pics of her, it looks like a TUGBOAT is moving her.
Proof of TUGBOAT towing sailing ship in crash. You just glimpse the aft of tugboat at very beginning of vid. Then the pilot house of tug moves along back of sailing ship.
Not saying tug intentionally moved sailboat into bridge but maybe was trying to intercept to prevent crash. But look at this pic of a NY harbor tug with pilot house and stack.