In order for a swim call to happen the waters have to be pretty calm and we need the ship to stop moving (obviously!). We were under engine, not sail, so that made it fairly simple.
For safety we launch the man overboard boat and it's manned by a team of two who monitor the swim area as well as crew on deck doing the same. Everyone was eager to get in the water so the crew swapped in and out of supervising roles so that everyone could have a turn to swim. There are two ladders set up for getting out of the water, and in as well if you don't fancy jumping off the side!