Assessing your chances of being caught by a giant wave
There is more truth than you might think in the old adage that every seventh wave is bigger than the rest. At random intervals, wave trains coming from different directions can fall in step with one another, literally riding on each other’s backs to form an exceptionally high wave—or an exceptionally low trough.It doesn’t need to be blowing a gale for this to happen, but if the weather is indeed stormy—and particularly if there is a contrary current to steepen the face of a giant wave—it will topple over and release its energy in the form of a plunging breaker large enough to overwhelm any small sailboat.

Top: The modest freeboard of a traditional cruising sailboat contributes to its overall beauty. Above: In sectional view, such a boat looks something like this. The full keel and resultant depth of hull body permit standing headroom below without a lot of freeboard.

Scientists maintain that the probability of such waves can be predicted. According to Laurence Draper, of the National Institute of Oceanography, 1 wave in about 23 is more than twice the height of the average wave, 1 in 1,175 is more than three times the average height, and 1 in 300,000 exceeds four times the average. There is an equal chance, Draper says, of an unusually deep trough occurring.See also Waves in Gales.

---