As we were taxiing out the pilot, obviously enjoying that we were a private charter, turned around with a smile asking "how low would you lot like to go?" ... Well we told him "go for it" and we pretty much had to take avoiding action to avoid the car ferry that some of our colleagues were traveling on.
Similar experience many years ago. Sat in the row behind the pilot I could see that the altimeter read about 50 ft and the pilot had to divert around a yacht mast. The French crew gave a friendly (if slightly worried looking) wave!