An Appeal to Arms
The submarine will surface every so often in order to provide the crew with opportunities for rest and recreation. While the ship is submerged in the water, the captain of the submarine may give one of the crew members permission to go for a swim in the water outside the vessel if the conditions are favourable.
Someone always needs to keep an eye out for potential danger, especially in the case that there is a shark attack. While some sailors take use of this time to get some much-needed vitamin D, others choose to instead utilise this opportunity to simply breathe in the fresh air and rest.