Believe it or not, Sailors in the US Navy spend most of their time on the water rather than in the water itself. Even aboard subs, the sea is definitely kept out. Among the dozens of “ratings” or Naval Enlistment Classifications (NECs) in the fleet very few are considered wet ratings. Navy Seals, Divers, SAR Swimmers, and coxswains operating small craft will spend plenty of time in the salty brine but for most Sailors, they stay high and dry.
The exception is an evolution referred to as a “Swim Call.” On long voyages, a couple of days are set aside for crew recreation aboard when there isn’t a port of call for liberty ashore. The ship anchors in warmer, relatively shallow waters and the entire crew gets a few hours of recreation jumping into the water off the ship and a chance to swim.
This of course creates problems of its own trying to keep track of all these sailors in the water who are just bobbing heads. There is no training for Swim Calls and for the skipper of the ship, losing a crewman during one of these recreation periods is a very deep concern. There are lots of risk factors to consider.
Open ocean swimming is not like being in a pool or at the beach. There is no bottom to stand on. I might be 200 ft below you. The swells can tire you out and make you hard to see in the water. For this reason, Swim Calls require a sea state of 2 or less.
Jumping off the ship is easy, getting back aboard can involve climbing a rope ladder or cargo net 30-50 ft back onto the ship. This is a lot harder than it sounds.
If the ship is not anchored to the bottom it can drift away from the swimmers at a pretty fast pace driven by the winds on the side of the hull. Not that you don’t naturally want to stay away from the hull while you are in the water. Bobbing on the surface, the ship looks absolutely massive to you and a bit scary.
The waves also slap up against the side of the ship so swimmers have to stay well clear of the hull to avoid having a swell bash them into the metal wall of the hull ad getting torn up by barnacles.
The weather and of course the temperature of the water itself is also a factor. Most of the world’s oceans are very cold and finding a place where the temps allow swimming without hypothermia can be a challenge. The weather can also change pretty quickly too so an accurate forecast is very important to assure safety on the swim. Lightning hits the ocean about a billion times a year and a strike in the water with 30-40 swimmers in it would kill them all instantly.
Lots of things live in the water too, like stinging jellyfish that can be very painful to encounter.
Of course, there is always the risk of shark attack in the open ocean. Sharks are generally pretty timid and cautious about what they take a bite of, but you never know. There is always that one shark that is hungry and doesn’t care too much about what it eats.
Once upon a time, as in the late 1980s, there were lookouts in the rigging armed with rifles(M-14s) in case a shark showed up. While the rifle may not have been very effective in killing a submerged shark, the shots would alert the swimmers that one was in the area and there would be a mad dash for the cargo nets to get out of the water as fast as possible.
For these reasons a Swim Call is never routine and the skipper is sweating bullets worrying about losing a crewmember.
Today, a Swim Call would include Search and Rescue Swimmers and small boats to keep watch over the swimmers who typically get 30-45 minutes of water time before the next batch of crewmembers get their chance to swim. The crew are usually given tickets with numbers on them and line up like they are going to chow to have their number called for swim time. When they come back aboard their name and number are carefully recorded to ensure they have recovered everyone.
I only participated in one Swim Call while I was in the Navy as a SAR Swimmer. It was off Andros Island in the Bahamas. I spent the entire time in a RHIB sweating in the sun in all my gear while the crew of the frigate went swimming. When it was over after 2 hours I was able to jump in the water for a few minutes and cool off while they readied the hoist to recover the boat. So it wasn’t exactly recreation for me. With all the guys splashing and swimming I was sure they’d draw a tiger or Bull shark, but we never saw one. I do remember being a bit unnerved when I submerged and looked down and all I could see was a vast expanse of dark blue water beneath me. The waters off the Bahamas were generally crystal clear so there were hundreds of feet of water below me. My main thought at the time was to make sure I didn’t lose anything off my rig.
We didn’t have any problems with any of the swimmers and only a few injuries from scrapes getting back aboard. One guy did fall off the cargo net back into the water, but he didn’t fall very far and didn’t land on anyone when he fell.
So it was a good day for a Swim Call.