or oa) is the maximum length of a vessel's hull measured parallel to the waterline.
It is the most commonly used way of expressing the size of a ship, and is also used for calculating the cost of a marina berth[1] (for example, £2.50 per metre LOA).
[7][8] In ISO 8666 for small boats, there is a definition of LOH, or length of hull.
[9] This may be shorter than a vessel's LOA, because it excludes other parts attached to the hull, such as bowsprits.
In some cases (particularly old yachts or vessels with bowsprits) LWL can be considerably shorter than LOA.