No person having in charge any raft of lumber, logs or timber, shall have more than eight (8) cribs of pine lumber, logs or timber, or not to exceed four hundred fifty (450) of hardwood lumber, logs or timber, towed in any raft in the harbor. All such rafts shall be drawn or towed at least fifteen (15) minutes apart while navigating the Cuyahoga River or old river bed. All lumber, logs or timber, making up or constituting such cribs shall be properly secured, so that the same shall not break adrift.