Complex sentence: He supervises the embarkation of supplies and equipment needed aboard Seaview during any underway mission, oversees Missile Room operations, oversees the mess deck, organizes work detail throughout the boat, from time to time serves as watch stander inside the control room.
Split into simpler sentences: He supervises the embarkation of supplies and equipment needed aboard Seaview during any underway mission. He organizes work detail throughout the boat, and, from time to time, serves as a watch stander inside the control room.