(k)for licensing and regulating catamarans plying for hire, and flats and cargo, passenger and other boats plying, whether for hire or not, and whether regularly or only occasionally, in or partly within and partly without any such port. [and for licensing and regulating the crews or any such vessels;] [Inserted by Act 6 of 1916, Section 4] and for determining the quantity of cargo or number of passengers [or of the crew] [Inserted by Act 6 of 1916, Section 4] to be carried by any such vessels [and may by such rules provide for the fees payable in respect of any such license, and in the case of [vessels] [Inserted by Act 6 of 1916, Section 4] plying for hire, for the rates of hire to be charged and the conditions under which such vessels shall be compelled to ply for hire, and further for the conditions under which any license may be revoked];