Submersible vessel

A submersible vessel comprising:

• a hull;
• a propulsor that propels the hull;
• a front sensor that sequentially detects locations of an elongated inspection target in front of the hull, the inspection target being disposed on a water bottom;
• a controller that controls the propulsor such that the hull passes through above the detected locations;
• a movable arm attached to an arm reference point of the hull;
• an inspection tool that is disposed at the movable arm and inspects the inspection target;
• and
• a position detector that acquires positional information including at least one of a position, an attitude, or a speed of the hull, wherein:
• based on the positional information acquired by the position detector, the controller estimates a pass-through position of the arm reference point after a predetermined time;
• the controller sets a virtual location between two adjacent locations among the locations;
• based on the positional information acquired by the position detector, the controller estimates the pass-through position of the arm reference point after the predetermined time;
• and
• the controller controls the movable arm such that before the predetermined time elapses, a positional relation between the arm reference point and the inspection tool becomes a positional relation between the estimated pass-through position and a target point on or above each location or on or above the virtual location.