Which of the following is NOT an open ocean position input?

• A. GPS
• B. Celestial
• C. Visual/Radar
• D. INS

Answer: (C)

The concept behind open ocean position inputs is centered on the various methods of determining a vessel's location when navigating in the vast expanse of open water. Global Positioning System (GPS), celestial navigation, and Inertial Navigation System (INS) are all recognized methods for accurately determining a ship's position based on either satellite technology, astronomical data, or internal motion sensors, respectively.

Visual and radar methods are typically used for navigation in coastal waters or near land where landmarks and navigational aids are present. In the open ocean, visibility can be limited, and identifying landmarks is generally not feasible. Consequently, relying on visual observations to determine position is not practical in this context, making it an inappropriate choice for open ocean navigation.

As a result, visual/radar inputs do not fit the criteria for typical open ocean navigation methods, reinforcing why this option stands out from the others as being not suited for open ocean positioning.