What is the formula for calculating the towing speed of a vessel?

The formula for calculating the towing speed of a vessel is derived from the characteristics of the towed vessel, specifically its waterline length. The principle behind this calculation is related to the speed at which a vessel can safely be towed without risking damage to either the towing vessel or the vessel being towed.

The correct answer incorporates the square root of the waterline length to determine a base towing speed, which is then adjusted by a percentage. The factor of 1.34 is used because it is a widely accepted constant that approximates the speed in knots based on the waterline length in feet. By subtracting 10% from this calculated value, the formula provides a conservative estimate that accounts for various operational factors, such as additional drag and the dynamics of towing. This adjustment is crucial to ensure safe and effective towing operations, especially under challenging conditions.

This methodology emphasizes the importance of calculating a towing speed that is not only theoretical but also practical, taking into consideration the safety margin needed when navigating with a towed vessel.