What is the X in X-mas?
A scuba diver, esp a professional or military diver (WWII Navy)
member of a U.S. naval underwater demolition team. In World War II their efforts reduced troop losses and facilitated the landing of men and supplies on enemy shores. Before an amphibious landing was made, frogmen reconnoitred the beach area. They measured the actual depths of the water, detected natural or man-made obstructions under the surface, and observed the enemy's defensive positions close to the water's edge. One of their most important functions was to destroy dangerous underwater obstructions. Frogmen were carefully chosen volunteers who were intensively trained and worked without weapons. After the war they performed research and rescue operations and served in Korea, Vietnam, and on other expeditions.