In the Marine Observer (55:203), T. Wilson Cameron reports one ship’s alarming encounter off the coast of Spain in the 1960s. At 5:20 a.m. one morning the moon disappeared:

I looked to port to see what type of cloud could obscure the moon so thoroughly, and was amazed — horrified, rather, to discover it was no cloud, but an immense wave approaching on our port beam. It stretched far north and south, had no crest, nor white streaks, and as it neared at quite a speed, I could see its front was nearly vertical. I yelled to the lookout man to come into the wheelhouse as he was on the starboard side of the bridge and could not see the wave.

As near as I could judge, about 80 to 100 yards away the wave started to break, and in another few seconds reached our ship and struck us fair abeam with three distinct separate shocks, sweeping our ship for her full length. Fortunately, the vessel rolled away just before the impact and this I am sure saved us from even more serious damage.

“The wave was higher than our foremost track — 85 ft above the water. As this wave approached from a direction 90 degrees different from the normal sea and wind, which had been northerly for a few days previously, I put its existence down to a submarine earthquake in the mid-Atlantic ridge. Certainly it appeared so much different from the normal wind-generated sea, of which I have seen thousands. There was no crest, nor white streaks, a nearly vertical front and quite fast approach.”