491. (1) Where under this Ordinance a ship is authorised or ordered to be detained, any commissioned officer of the Bangladesh Navy, or any Principal Officer, Pilot or Collector of Customs may detain the ship. (2) If any ship after detention, or after service on the master of any notice of, or order for, such detention, proceeds to sea before she is released by competent authority, the master of the ship shall be punishable with fine which may extend to one lakh Taka. (3) If a ship so proceeding takes to sea, when any person authorised under this Ordinance to detain or survey the ship is on board thereof in the execution of his duty, the owner, master or agent of such ship shall each be liable to pay all expenses of, and incidental to, such person being so taken to sea, and shall also be punishable with imprisonment for a term which may extend to six months or with fine which may extend to twenty thousand Taka, or with both. (4) When any owner, master or agent is convicted of an offence under sub-section (3), the Magistrate convicting him may inquire into and determine the amount payable on account of expenses by such owner, master or agent under that sub section, and may direct that the same shall be recovered from him in the manner provided for the recovery of fines.