Initial reports indicated that the assistant captain at the ferry's controls may have lost consciousness in the crucial final minutes as the ferry approached land. Because the assistant captain was apparently no longer controlling the boat's speed or direction, the ferry is believed to have been traveling at its full service speed when it crashed.
For safety reasons, New York City's operating rules for the Staten Island ferries require two licensed officers, the captain and the assistant captain, to be present in the controlling pilothouse when a boat is in motion. Investigators were trying to determine if the boat's captain was in the forward pilothouse, and if so, why more effective measures were not immediately taken to slow, stop or turn the ferry after the assistant captain lost control.
The accident is under investigation by the National Transportation Safety Board. Federal and state prosecutors are conducting criminal investigations.
The 310-foot-long, double-ended ferry Andrew J. Barberi can carry up to 6,000 passengers, but only about a quarter of that number were aboard on the mid-afternoon trip.
The ferry departed lower Manhattan at 1500 for the 20-minute trip across Upper New York Bay. Winds were generally from the west and gusting up to 45 mph, but Staten Island ferries have historically operated without incident in more severe conditions.
Normal service speed for Andrew J. Barberi is 18.5 mph. As the boat approached the Staten Island ferry slips, it failed to slow or turn toward the intended slip, according to passengers and witnesses on shore.
Approximately 600 feet past the normal slip, the ferry collided with a corner of a maintenance pier constructed of wooden pilings and concrete decking. The main deck's forward starboard-side plating struck the pier's corner. As the boat continued ahead, the pier structure tore away the vessel's welded steel plating and windows along the main deck for almost the entire length of the ferry. As the pier's debris penetrated into the main-deck passenger compartment, seats were torn away and interior structures, including ceiling panels and stairways, collapsed onto passengers. The majority of the deaths and injuries occurred in the forward starboard area.
Andrew J. Barberi, which went into service in 1981, was the first boat in New York City's ferry fleet to use cycloidal propulsion instead of conventional propellers. That design made the ferry highly maneuverable. The cycloidal drives can thrust with equal efficiency either ahead or astern, according to a paper delivered by Edward J. Ciechon and Larry N. Hairston to the Society of Naval Architects and Marine Engineers' Philadelphia Section in 1979.
They wrote that the vessel's "ahead/astern (speed) control is by a pair of levers which move in a fore and aft direction. The amount of pitch is determined in proportion to the movement of the levers. The two handles which control the bow and stern propellers are located adjacent to each other, thereby allowing one hand to control both propellers simultaneously." The report noted that maneuverability was enhanced because the cycloidal thrust forces could also be generated in an "athwartship direction by varying the propeller pitch."
Another report by Carl Berkowitz, Leonard Piekarsky and Allen Chin presented to SNAME's Metropolitan Section concurred that Andrew J. Barberi's "maneuverability is unsurpassed" with the cycloidal system. The report indicated the ferry's four General Motors EMD 16-645E6 diesel engines each delivering 1,750 hp at 800 rpm drive two 40G/250 Voith-Schneider cycloidal propulsion systems. Each has five blades that are 7 feet, 10.5 inches long that move through an orbit 13 feet, 1.5 inches in diameter.