I stand corrected - there are two other crewmen visible at about 2'30" - they are standing in the hatchway, wearing T-shirts and no safety gear at all, and are talking to each other, obviously not on watch nor keeping a lookout. They aren't visible in subsequent footage. But again, there are obvious breaks in the filming, so there is no real idea of how long a time period this video actually covers.

Most yachties who sail the sea routes are well aware that a big container ship doing 20 knots or so can come up over the horizon and run you down in about 10 minutes. Which is why you try to keep a continuous lookout.

A big sailing vessel like the Bounty would have radar reflectors, possibly its own radar set and will give a big signature on anyone else's radar, but you shouldn't be trusting the other fellow to be looking out for you... Yachts are regularly lost in the sea routes around Europe like this. Big ships are supposed to have watchkeepers on duty and mostly they do, but mistakes do get made every now and then.