Only a green one is missing. These kayaks sit atop some of the zodiacs used during the Antarctic expedition. Everyday, the Zodiacs would be lowered one at a time, by crane, into the water prior to our expedition. Then, upon our return, they would each be raised back onto the ship. Since we would go on two expeditions a day, this whole routine happened twice a day, which must've been a lot of work and coordination for the crew who always got it done.
From all my other travels, this was definitely one of the most exciting ways to travel. I've never been on a "normal" cruise, but I'm pretty sure you're not traveling by zodiac on those as you just dock at a giant cruise ship pier and walk on/off. While there's nothing inherently challenging about walking down and getting in/out of a zodiac, it is a bit more exciting in general. Also, if you sit near the front, and the waves are choppy, higher chance you're gonna get an icy cold shower on the zodiac ride.
Three kayaks that remind me of peppers, resting on some zodiacs.