Hughie was stationed in Alaska without the family. The family was suffering for the Navy in Hawaii. (However, the author had not been born yet.)
His squadron was sent there to keep an eye on the Soviet Union and their spy operations because, as Sarah Palin said, you can see Russia from Alaska.
One day, Hughie was sent out looking for a Soviet spy ship. As you suspect, a spy ship doesn't look like a spy ship. It doesn't have SPY SHIP written on the keel or the fore/aft or whatever. (Navy skipped a generation.) But...how many pleasure boats are out in the middle of the North Pacific or Bering Sea? So, really. The Pacific is a huge ocean and finding one ship in that vast ocean has to be like a needle in a...in a...ok, so it's like trying find one ship in the vast ocean.
Hughie's crew is the one who found the ship! I guess once you see it, it's hard to hide the ship, unlike submarines, which are marines that are sub...I guess. (Remember, skipped a generation.) So they start taking pics of the spy ship - which interestingly enough was called SPY SHIP. As they circled the ship they took lots of pictures so they could guess at their capabilities, I guess.
Side Note: as a rule, airplanes don't fly directly over a ship. I didn't know that, did you?
The pilots and crew could see there was someone on the deck reading, I guess to make it look like a pleasure craft...in the middle of the ocean...near Alaska...ok, I'm not buying it either.
When they accomplished their mission, they flew back to their base and got the pictures developed. For those of you born in the 2000's, that means they did not have automatic access to the pictures and none of them were selfies.
One particular picture made them laugh. The picture of the person on the deck reading was a man dressed as a woman. The book he/she was reading? The Bible.
Those Soviets were truly a riddle, wrapped in a mystery, inside an enigma*.
The mission was a success!
*-Winston Churchill said that about the Russians in 1939. Still rings true today, eh?