What strength is required when operating the main steering of a ship?

The requirement for adequate strength when operating the main steering of a ship acknowledges the need for a balance between responsiveness and control. Main steering systems are designed to be operable with a level of strength that doesn't overwhelm the operator but is sufficient to effectively maneuver the vessel under typical conditions.

Using "adequate strength" means that the steering system should be manageable while still allowing the operator to exert enough force to steer the ship as needed, particularly in challenging situations such as strong winds or rough seas. This ensures that operators can maintain control without excessive fatigue or risk of injury, promoting safe navigation.

The other choices imply either a lack of strength or an excessive requirement: minimal strength might not provide enough control in all situations, maximum strength could indicate a need for unrealistic physical exertion, and unrestricted strength could lead to potential misuse or loss of control over the steering system. Therefore, the focus on adequate strength reflects a realistic and practical approach to steering operations onboard a ship.