What does the term "offset -2" in relation to navigational draft refer to?

The term "offset -2" in relation to navigational draft refers to the reduction of the draft based on specific conditions or adjustments. In navigation, particularly for vessels, the draft is the vertical distance between the waterline and the bottom of the hull (keel). When a draft is said to have an offset of -2, it indicates that the effective draft has been reduced by 2 units, which could be feet, inches, or another relevant measurement.

This reduction can be attributed to several factors, such as changes in vessel loading, the vessel’s position (for example, if it is not fully loaded), or certain navigational considerations where a temporary adjustment is made to account for safety or operational efficiency. Understanding the concept of draft adjustments is critical for safe navigation, as it helps the operator assess whether the vessel can safely navigate through specific waterways.

The other options relate to different aspects of vessel operations or safety criteria but do not capture the essence of what "offset -2" signifies in terms of navigational draft.