It probably dissipated shortly after doing its thing on the cruise ship. A "freak" wave is called that because it's the product of two or more wave-generating sources -- two storms, for example -- that send out waves and they pile up on one another. This may have been a storm that sent out a forty-foot wave that encountered a thirty-foot wave from another storm that piled up on it and they traveled together for a while. Result: a 70-foot wave. But only temporary.
In 1965, my cruise ship to Vietnam, the USNS Gordon, was laid into by one of those at night while we were watching a movie on deck (Lawrence of Arabia); it was terrifying. I thought we were going to capsize.
There actually are some pictures of a few of these on the net (and some of the damage wrought); if I didn't have to leave for a fencing tournament right now I'd post some.
They're out there if you search on rogue waves though; One off South Carolina I remember. Some from South Africa.