Yeah I always think of them as whole city blocks hurdling through the sea -- they travel at 20+ knots which is actually crazy fast -- that guy speeding by in his motorboat shooting up a big wake is probably not even going as fast. But where the motorboat can come to s top in a minute or two, the container ships require dozens of miles to come to a stop! Through reasons of physics I don't quite understand it apparently is easier to go faster the longer a ship's hull is. As mind boggling as it seems, aircraft carriers are among the fastest ships at sea. Their top speed is classified but I think they've been reliably reported to be able to reach more than 90 knots. It's insane!!