I don't remember which navy I was in when I first heard the term "silly buggers," but the meaning was clear. It included some sensible exercises like "man overboard" drills, but the heart and soul of the game was high-speed maneuvers by ships traveling in close company. These sometimes got quite exciting, because ships don't have brakes.
Off the coast of Lebanon, in 140 meters of water, is the wreck of the British battleship HMS Victoria, which sank in 1893. It is the world's only vertical wreck, because its bow is plunged deep in the mud but its stern is only 70 meters below the service — "like a tombstone," said one of the divers who found it in 2004. And it was "silly buggers" that did for it.
The British Mediterranean fleet was traveling in two parallel lines when Adm. George Tryon decided to reverse course — and to make it interesting he ordered the lead ships of each line to make the turn inward, toward the other line. In theory the two lines of ships should have ended up traveling in the opposite direction, but much closer together.