http://geology.com/records/biggest-tsunami.shtml

(The link above includes Ulrich's account -- which seems lucid and and rational). It clearly wasn't a wave over 1,000 foot high when it reached him, and maybe (?) his trusty anchor farther down the Bay.

The short summary from another post is a bit more eye grabbing...

Alaskan Mega-Tsunami
BY THOR JENSEN
This one goes out to all the extreme sports fans out there. In 1958, an underwater earthquake loosed 40 million cubic yards of rock from a cliff 3000 feet above the sea in Alaska's Lituya Bay. The impact when that huge stone smacked the water created the largest wave ever measured on Earth – a staggering 1,720 feet. And Howard Ulrich and his seven year old son were right in the middle of it. The duo were moored in the bay, and when Ulrich saw the wave approaching he couldn't release the anchor in time. So he let out the chain as far as he could and started his engine. Amazingly enough, his boat managed to catch the wall of water at the right angle, being carried over the shore and back into the center of the bay.