{{Short description|Line where the hull of a ship meets the surface of the water}} {{Other uses}} [[File:Dias ferry waterline 2.jpg|thumb|Waterline of a ship. The mark above the waterline indicates the Plimsoll line]] The '''waterline''' is the line where the hull of a ship meets the surface of the water.
A waterline can also refer to any line on a ship's hull that is parallel to the water's surface when the ship is afloat in a level trimmed position. Hence, waterlines are a class of "ships lines" used to denote the shape of a hull in naval architecture lines plans.{{sfn|Kerchove|1961|p=901|loc=Waterlines}}
The load line (also known as Plimsoll line) is the waterline which indicates the legal limit to which a ship may be loaded for specific water types and temperatures in order to safely maintain buoyancy.{{sfn|Kerchove|1961|pp=464-465|loc=Load Waterline}}
For vessels with displacement hulls, the hull speed is defined by, among other things, the waterline length. In a sailing boat, the waterline length can change significantly as the boat heels, and can dynamically affect the speed of the boat.
== Aircraft == {{excerpt|Lofting coordinates|Waterline}}
==See also== * Waterline length
== References == {{reflist}}
== Sources == * {{cite book | last=Takahashi | first=T. | title=Aircraft Performance and Sizing, Volume I: Fundamentals of Aircraft Performance | publisher=Momentum Press | year=2017 | isbn=978-1-60650-684-4 | url=https://books.google.com/books?id=IbipCwAAQBAJ&pg=PT77 | access-date=2024-07-02}} * {{cite book | first1 = René de baron | last1 = Kerchove | date = 1961 | title = International Maritime Dictionary: An Encyclopedic Dictionary of Useful Maritime Terms and Phrases, Together with Equivalents in French and German | edition = 2 | publisher = Van Nostrand Reinhold | page = | isbn = 978-0-442-02062-0 | oclc = 1039382382 }} * {{cite book | author=United States. Air Force | title=Air Force AFM. | publisher=Department of the Air Force | year=1960 | url=https://books.google.com/books?id=m2zzfwQkmBcC&pg=SA14-PA20 | access-date=2024-07-02}}
{{shipbuilding-stub}} Category:Shipbuilding