unit 1 was circling while waiting on the wappoo cut bridge to open. there was a stronger than average incoming tide that caught unit 1 broadside and took the vessel towards the bridge. the bridge had begun its opening procedure /lights etc...unit 1 turned to starboard to go through the bridge without being sideways at the last minute. unit 1 did not have enough clearance striking the mast on the bridge. the mast collapsed on to the deck.