The incident occurred on the deck of the vessel as they were preparing the 2nd piggyback anchor assembly for deployment. They had just finished connecting the anchor to the chain and were moving away from the work area on the deck of the vessel. The port hydraulic anchor handling jaw retracted releasing the chain. This caused a sudden jerk on the anchor, pulling the anchor down the deck and over the stern. Observers of the incident state that the anchor was off the back of the vessel within 2 seconds. The Chief Mate was struck by one of the anchor stabilizer bars as it moved down the deck. His left leg was broken just below the knee.