What is the origin of the idiom 'In your wheelhouse'?

Answer 1

The idiom "in my/your/his wheelhouse" appears to have originated in Baseball, as far back as the 1950s, perhaps before that. It's used to describe a pitch that comes across the plate in the batter's "sweet spot," a place where he can reliably make solid contact with the ball. The figurative origin of the term is less easy to pin down. The metaphor may have been meant to suggest rotational force, as with a railroad wheelhouse (also called a roundhouse), a platform used to spin a train engine or car for the purpose of transferring it to a different track. Or it may may have come from the nautical meaning of wheelhouse (aka pilothouse), suggesting a place where one has complete control, as on a ship.

Answer 2

Initially, this was a nautical term. A wheelhouse is exactly what it sounds like: the little “house” on a ship where the captain stands, and where the ship’s wheel and other navigational equipment are located. This is where the captain steers the ship.

In the 1950s, this term was picked up by baseball announcers and reporters. They began to refer to a batter’s “wheelhouse,” meaning the area of the strike zone where a batter swings with the most power.

In the 1980s, the meaning of this term expanded once again. It came to mean an area or field in which a person excels, a person's area of expertise.