By Ben Ellison
Ocean-Clocks tide table clock
Tide clocks don’t really qualify as marine electronics, but I want to make amends for past skepticism regarding the genre. My gripe was that the extra hand on any tide clock (or watch) only tracks lunar orbit time, which may be the most powerful constituent in a tide prediction formula but is only one of dozens. For instance, in places where lunar declination is also a major factor, like the U.S. Gulf Coast, there’s often just one high tide per day, and a tide clock is nearly useless. It really takes a PC or plotter processor to reliably predict tides everywhere to the minute. On the other hand, to-the-minute accuracy is a bit of an illusion as tides change very slowly near high and low, and for many of us on the Atlantic and northern Pacific Coasts, those highs and lows are closely associated with the moon’s orbit.
Ocean-Clocks’ clever new localized design not only focuses on areas where lunar time works well, it also gives you a sense of the tidal relationships in that area. The Cape Cod version I tried made graphic sense of the relative tide at 20 Massachusetts stations from New Bedford to Provincetown, more than making up for its plus/minus one hour maximum inaccuracy. Plus, with a little figuring, it also tracked the moon’s passing. U.S. distributor Windward Instruments offers these clocks in several case styles for 17 East Coast regions plus Washington’s Puget Sound, with the hunky solid brass design shown costing $349.
Windward Instruments Phone: (800) 210-0492. www.bellclocks.com.
This article originally appeared in the August 2004 issue of Power & Motoryacht magazine.