Length between perpendiculars

Graphical representation of the dimensions used to describe a ship.

Length between perpendiculars(often abbreviated asp/p,p.p.,pp,LPP,LBPorLength BPP) is the length of ashipalong the summer load line from the forward surface of thestem,or main bow perpendicular member, to the after surface of thesternpost,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 ofvesselsthis is, for all practical purposes, a waterline measurement. In a ship with raked stems, naturally that length changes as thedraughtof the ship changes, therefore it is measured from a defined loaded condition.

See also

• Length overall

References

• Hayler, William B.; Keever, John M. (2003).American Merchant Seaman's Manual.Cornell Maritime Pr.ISBN0-87033-549-9.
• Turpin, Edward A.; McEwen, William A. (1980).Merchant Marine Officers' Handbook(4th ed.). Centreville, MD: Cornell Maritime Press.ISBN0-87033-056-X.

External links

• Perpendiculars and Length Between Perpendiculars