I copied this:

According to Ned Mayo (see Ref), the highest reliably measured ocean waves
were reported by officers of the Navy oiler USS Ramapo in the North Pacific
on February 7, 1933. By triangulation on the ship's superstructure, they
measured a wave height of 34 meters (112 feet) peak to trough. The period of
the wave was 14.8 seconds and its wavelength was calculated to be 342
meters. Using the wave velocity expression for this wavelength in the deep
water limit, the wave speed is calculated to be 23 m/s. Mayo calculates the
power of one meter length of such a wavefront to be 17,000 kilowatts!
The crew of the Ramapo measured these waves and lived to tell about it
because their relatively short ship(146 m =478 ft) rode these very long
wavelength ocean mountains without severe stresses on the craft. Mayo
expresses concern about the safety of some modern giant ships (250 meter
length) in such seas.

From http://hyperphysics.phy-astr.gsu.edu/hbase/watwav.html

Take it for what it is worth.

BS

wrote in message
...
http://news.bbc.co.uk/2/hi/science/nature/4739741.stm

Key excerpts:

Hurricane Ivan generated a wave more than 90 feet (27 metres) high -
thought to be the tallest and most intense ever measured

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The distance between the crest of the biggest wave and its trough was 91
ft (27.7 metres) but they suspect the instruments missed some waves that
were as tall as 132 ft (40 metres).