New sub, to me, but it still seems familiar to the trainers we had last year. Oxygen needs to be monitored in about the same rate as CO2 is being scrubbed out. This maintains proper breathing air and constant cabin pressure. I flood the soft ballast tank and thrust my way to the bottom. Squids have been here all month mating and laying eggs at night, and the fishery for them has been going at full tilt.
Light is dim due to the thick plankton, but there's enough light to see and navigate.
I give the required life support readings to the topside dive supervisor, and am given a compass heading that will take me away from the ship and its anchor and chain. I lift off the bottom and begin motoring along a line toward Hopkins Reef. Along the way I spot a small gray fat ray with a black tail. A chance to try out the manipulator arm and see if I can collect something. OK, remember how to enable the manip arm.