Keeping a close eye is an essential part of coastal navigation in British Columbia. Crab pots, kelp beds, floating logs, and the deceptive knot of twigs hiding a large root-ball and log below require a careful watch – a fun task for crew as they keep a careful eye out for whales and other wildlife.
Cruising in tidal waters bring special dangers for skippers of vessels of all sizes. Rapid currents must be timed to ensure control in many areas throughout B.C. Skippers must carefully plan and remain alert to the dangers and limitations of one’s vessel when entering fast running waters. Large tidal ranges, in some areas in excess of 12′, challenge even the most experienced skipper when scope and swing radius can significantly change overnight.
Tidal Ranges Increase Dangers
As the gravitational pull of the Sun and Moon affect the rise and fall of the ocean twice daily, tidal currents gain speed throughout our archipelago. And during the full and new moons, Spring Tides bring larger tidal ranges twice monthly. This past season, extraordinarily large tides resulted in negative tides – a phenomenon more commonly seen in U.S. waters that set chart datum as the mean low.
In addition to the changes in water depth and speed wrought by large tidal ranges, dangers lurk below the surface in the most unsuspecting places. And when these large tidal ranges enter our active logging region, they wash large logs off the shore. Deadheads, large vertical logs that can appear as mere twigs at the waters surface, can appear our of no where.
In the days following high tidal ranges, mariners must keep a careful watch to avoid monster logs and hidden deadheads. And when entering areas with strong current where timing slack current, mariners must take into account the strong potential for hidden deadheads hidden in the building energies of back eddies.
Yes – this really happened. While cruising this summer, this water-laden log disabled the propeller on a twin prop power boat. A diver was required to remove the prop before the vessel could enter the marina because the log extended beyond the hull.