It's been a while since I played this game, but if memory serves me correctly......I believe I walked away from the ship for a while, snooped around the docks and then went back to where the crates and things are. The cat will stroll by. You need to position yourself in just the right spot (again, if memory serves me correctly...according to the walkthrough I used I had to move farther to the left of the crate mentioned in order to get the cat).
Perhaps someone else may be better able to help you. Don't dispair.
A WINNER never quits, and never will a Quitter WIN!! LINDA
Snatch up YOUR next Adventure ADVENTURE GAMES GALORE!!