게 분명했다

it was clear that

→ 것+이
phrase Rare #23,017
it was clear that 게 is a shortened form of 것이 here, referring to the preceding clause.
KO: 그가 집에 있는 게 분명했다.
EN: It was clear that he was home.

그가 준 음식을 보니 선원들은 결혼을 아주 잘한 게 분명했다.

Seeing the food he gave them, it was clear that the sailors had married very well.

섀도스의 돛대가 보일 게 분명했다.

The mast of the Shadows would surely be visible.

해안 가까이는 아닌 게 분명했다.

It was clearly nowhere near the coast.

일반 드라이버는 철로 만든 게 분명했다.

The regular driver must have been made of iron.