All ballast logs, fending-off floats, or camels, when used by vessels at docks, must be properly fastened by chains, wire cable, or ropes in such a manner that they cannot float through their fastenings if disturbed by the displacement of water caused by any passing vessel or other cause, and all such floats must have at least one preventer cable attached to it on end with the other end securely fastened to the ship or dock.