Assessing Cuauhtémoc's Brooklyn Bridge collision

What may have caused the Mexican ship Cuauhtémoc to strike the Brooklyn Bridge?

A variable-pitch propeller failure or fouling is plausible, but the accident report is needed before drawing a conclusion.

Cuauhtémoc's lights appeared to remain on while its movement did not match the expected response to engine commands. An apparent acceleration astern prompted the theory that the variable-pitch propeller had failed to change pitch, perhaps because of mechanical trouble or fouling. The accompanying tug had detached to reposition when the ship was expected to have its own propulsion available. If the propeller continued driving the ship backward, a tug might only have reduced the impact rather than stopped the casualty. This was a provisional assessment made before the accident report, and the cause remained uncertain.