All managers and keepers of public ferries shall afford applicants immediate passage across the ferry at all hours, day and night, at the usual fees and charges. Every ferryman or ferry keeper of any public ferry who, by absence from the ferry or by negligence, causes the detention and delay at the ferry of any bona fide applicant for passage at such ferry for the space of one hour or more shall, upon conviction, be guilty of a misdemeanor and shall, upon conviction, be fined five dollars or imprisoned thirty days for each offense. But this section shall not apply to steam or free ferries.