As Scoot thought about it, about the work March had been doing, he realized that there was a great deal in common in their fields. Flying a plane wasn’t much like handling a submarine, but both of them got away from the normal positions of most people. The flier got away from the earth’s surface in one direction. The submariner got away from it by going under. They both handled craft that could travel in a three-dimensional sphere, not just over the surface like a tank or a battleship. “March practices coming up with a Momsen Lung,” Scoot told himself, “while I practice coming down with a parachute. That Lung’s just a sort of underwater parachute.” A plane was just a vehicle to get explosives into position for firing at the enemy and so was a submarine, Scoot concluded. And sometimes they even handled the same explosives—torpedoes! “Now if someone would just invent a flying submarine,” Scoot thought, “March and I could get together again. But I guess that’s not very likely outside the comic strips. When you think of the terrific water pressure a sub has to stand, you can’t very well imagine hooking wings on to something that heavily plated with steel. And think of the batteries! No—I’m afraid March and I will be separated for some time. It seems a shame, though, sub and plane ought to make a mighty fine team.” The next week, as Scoot started off from Corpus Christi for the training carrier off the shores of Florida, March was setting off on one of the most important underwater trips of his training. It was a trip of two days on which March was to act throughout as navigation officer, still his specialty despite his training in every other job on the ship. March knew his navigation thoroughly while he was still on surface ships, but with the intensive extra study he had gone through at New London, especially on dead reckoning and “blind” navigation for underwater travel, he was a master. During the trip, on which Stan Bigelow also acted as engineering officer in charge of the Diesels and motors, they got the real feeling of being on patrol. They simulated traveling through enemy waters and so ran submerged most of the daylight hours, the Skipper taking a look around occasionally with the periscope. Numerous drills were also rehearsed during the voyage—fire drills, man-overboard drills, crash dives. They simulated a chlorine gas danger, acting as if the sea water had got into the batteries to give off the deadly fumes. Gas masks were out in a hurry and the battery room was sealed off with only two “casualties.” “The only thing we haven’t tried on this trip,” March said at mess the first evening, “is some of the first aid we’ve learned.” “Well, if someone will volunteer to simulate appendicitis,” the Skipper laughed, “I’m sure Pills will try an operation. But you forgot something else we haven’t tried—a depth-charge attack.” “I’d just as soon skip that, sir,” Stan said, “at least until the real thing hits me.”