The captain and pilot at the bridge of a US ferry that crashed into a stone breakwater have been placed on paid administrative leave.

The two unnamed men were stood down by the Woods Hole, Martha's Vineyard and Nantucket Steamship Authority five days after the smash involving the 393-passenger fast ferry Iyanough (built 2007) on 16 June, the Inquirer and Mirror reported.

Fifteen people were injured when it slammed into a stone breakwater near the entrance to Hyannis Harbor.

Mechanical error does not appear to be a factor in the crash, the shipowner said.

It did not specifically identify operator error as a possible cause, however.