What happens when the block coefficient exceeds 0.68?

When the block coefficient exceeds 0.68, the modified tabular freeboard is indeed increased. The block coefficient is a measure of the fullness of the ship’s hull, calculated as the ratio of the volume of the submerged portion of the hull to the volume of a rectangular block with the same length, breadth, and depth.

A block coefficient greater than 0.68 indicates that the vessel has a fuller form, affecting its hydrodynamic properties and stability. As a result, the freeboard, which is the distance from the waterline to the upper deck of a ship, may need to be adjusted. Increasing the modified tabular freeboard compensates for the increased buoyancy and stability provided by a fuller hull form.

This adjustment ensures that the vessel maintains adequate safety and stability levels while addressing the specific characteristics brought about by the increased fullness of the hull.