Where any person is convicted of an offence under this Act, the Court may, in addition to awarding any punishment, order that any costs incurred in connection with the retention or custody of the vessel during the pendency of any proceedings for the prosecution of an offence under this Act, as reduced by the amount, if any, realised out of the use of the vessel by the authority with whom such vessel was retained or kept in custody, shall be payable by the person convicted.