Terminology

Ships Measurements

There are important terms that we should know about the ship’s measurements.

We use different terms and limits to define the ship size in Length, Breadth, Depth, Volume, Capacity, Weight, etc., in the maritime world.

Usually, people confused the terms used to measure mass or weight with volume. So below, we have categorized the measurement with definitions.

Length overall (LOA)

It is the maximum length measured from the extreme forward and aft points of the vessel. It is the most common way of expressing the length.

Most importantly LOA is considered to calculate the cost of a marina berth.

Length between perpendiculars (LBP)

It is the length between the forward and the aft perpendiculars parallel to the summer load line.

Aft perpendicular is the perpendicular drawn through the axis of the rudder post to the loaded waterline.

Forward perpendicular is the perpendicular drawn through the intersection of the stem post and the loaded waterline.

This is an important measure to determine the lightweight coefficient when a new ship is designed.

Length at the waterline (LWL)

It is the length of the ship at the level of water she floats. This measurement is useful to calculate hull speed, bow, and stern waves occurrence, etc.