潜せん望ぼう鏡きょう深しん度ど

noun

periscope depth

Submarine depth at which the periscope can be used to observe the surface while the hull remains submerged.

• 潜せん水すい艦かんは潜せん望ぼう鏡きょう深しん度どまで浮ふ上じょうした。

  The submarine rose to periscope depth.