NEW YORK (CBSNewYork) — The high-speed commuter ferry that slammed into a pier in lower Manhattan last week had a damaged propeller, but it’s unclear if that was a factor in the crash or if it was damaged in the accident, the National Transportation Safety Board announced Thursday.

At least 74 people were injured last Wednesday when the Seastreak Wall Street, coming from Highlands, N.J., slammed into a dock at a Pier 11 at South Street Seaport during the morning commute. The boat was loaded with 326 commuters and five crew members.

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The force of the crash peeled back the hull of the ferry like a tin can.

PHOTOS: Seastreak Ferry Accident At Pier 11

The NTSB dispatched 11 investigators to determine the cause of the crash.

The team has so far interviewed crew members and at least 13 passengers.

An underwater survey of the vessel revealed damage to the port propeller and a more complete hull survey will be conducted when the vessel is hauled from the water for repairs, the NTSB said.

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The agency has also requested the Army Corps of Engineers to conduct a survey of the approach to Pier 11 to determine if there are any underwater obstructions.

Investigators have also tested the ferry’s steering systems and so far have not found a problem.

The captain claims the controls and engines failed as he tried to dock. Over the weekend, the investigative team started testing  the main engines and control systems, the NTSB said.

The Seastreak Wall Street had two minor docking incidents in 2009 and 2010 before getting a major overhaul last year, reducing its weight and increasing its fuel economy.

The vessel was built in 2003, and was extensively remodeled and retrofitted just last summer to make it more efficient, as well as to cut carbon dioxide emissions. The four original engines were replaced with two new ones, and the original water-jet propulsion units were replaced with two controllable pitch propellers.

Investigators are still trying to determine if the modifications had an impact on the Seastreak Wall Street’s performance and response.

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Investigators are also analyzing data from the engine control modules and video from several onboard cameras.