Length between perpendiculars (often abbreviated as p/p, p.p., pp, LPP, LBP or Length BPP) is the length of a
ship
A ship is a large watercraft, vessel that travels the world's oceans and other Waterway, navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally disti ...
along the summer load line from the forward surface of the
stem, or main bow perpendicular member, to the after surface of the
sternpost, or main stern perpendicular member. When there is no sternpost, the centerline axis of the rudder stock is used as the aft end of the length between perpendiculars.
Measuring to the stern post or rudder stock was believed to give a reasonable idea of the ship’s carrying capacity, as it excluded the small, often unusable volume contained in its overhanging ends. On some types of
vessels this is, for all practical purposes, a waterline measurement. In a ship with raked stems, naturally that length changes as the
draught of the ship changes, therefore it is measured from a defined loaded condition.
See also
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Length overall
Length overall (LOA, o/a, o.a. or oa) is the maximum length of a vessel's hull measured parallel to the waterline. This length is important while docking the ship. It is the most commonly used way of expressing the size of a ship, and is also ...
Citations
References
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External links
Perpendiculars and Length Between Perpendiculars
{{Ship measurements
Shipbuilding
Ship measurements