When discussing length overall of a sailing vessel or any type of surface craft, the measurement includes more than the length of the usable space of the vessel. Both the fittings on the bow in the form of a bowsprit and the stern or rudder of the boat must be measured and taken into account when figuring the length overall of any boat. In some cases, the length of the vessel from end to end at the waterline where the ship contacts or sits in the water is referred to as the length overall of the vessel. Often synonymous with berthing length or mooring length, this measurement commonly refers to the measurement of the vessel's hull.
Commonly referred to as LOA, the measurement is the most common for referring to a boat's size. When compared to the length of hull dimension (LOH) the length overall can be much greater than the LOH measurement of any vessel. The loaded at waterline (LWL) measurement can be and often is much less than the length overall, especially in sailing boats where a bowsprit may be used on the bow of the boat. Where the LOA is used to define berthing costs, the LWL is a more accurate method of determining a vessel's performance when loaded.
Depending on the purpose of the measurement, a sailing ship's length overall may exclude the length of the bowsprit. If measuring the vessel to be hauled on a truck and transported on a roadway, the length of the bowsprit may be included to accurately be fitted behind the truck on a trailer. If, however, the vessel is simply being measured to store in a berth or mooring spot, the bowsprit measurement may be excluded, and only the dimensions of the ship's hull may be factored into the cost. When including the bowsprit, the terminology for defining the total length measurement is often called the sparred length, which is the total length including bowsprit and mooring length.
In some smaller vessels, the length overall refers to only the usable deck space or hull space. In the case of a submarine, the total measurement from tip of bow to end of rudder or propeller hub is used in determining the total length of the vessel. To arrive at the correct length overall of a vessel, it may be conditional on which part of the world the ship is being measured in as well as for what individual purpose the measurement is being taken.
