Editing Sail components (section)

===Edges===
The top of all sails is called the ''head'', the leading edge is called the ''luff'', the trailing edge is the ''leech'', and the bottom edge is the ''foot''.

*''Head'' {{anchor|Head}}– The ''head'' is the upper edge of the sail, and is attached at the throat and peak to a gaff, [[yard (sailing)|yard]], or sprit.{{sfn|King|Hattendorf|Estes|2000|page=283}} For a triangular sail the ''head'' refers to the topmost corner.
*''Leech''{{anchor|Leech}} – The aft (back) edge of a fore-and-aft sail is called the ''leech'' (also spelled ''leach'').<ref name="SAIL Magazine 101" /> The ''leech'' is either  side edge of a symmetrical  sail—triangular or square.{{sfn|King|Hattendorf|Estes|2000|page=283}}{{sfn|King|Hattendorf|Estes|2000|page=271}}{{efn|name=oxford|The traditional terminology is for the two leaches of a square sail to be referred to as the "weather" and "lee", depending on the bracing of the yards, or "port" and "starboard".<ref>''The Oxford Companion to Ships and the Sea," Peter Kemp, p. 739</ref>}} However, once a symmetrical sail has wind blowing along its surface, whether on a [[Point of sail#Reaching|reach]] or [[Point of sail#Close-hauled|close-hauled]], the windward leech may be called a ''luff'' (see below).
*''Luff''{{anchor|Luff}} – The forward (leading) edge of a fore-and-aft sail is called the ''luff'', and may be attached along a [[mast (sailing)|mast]] or a [[Stays (nautical)|stay]].<ref name="SAIL Magazine 101" /> When on a reach, the windward leech of a spinnaker (symmetrical or not) is called the luff<ref>{{Cite book |chapter-url=https://books.google.com/books?id=5vMeEL0Pts0C&q=Spinnaker+luff&pg=PA106 |title=The Best of Sail Trim |last=Stanton |first=John R. |date=2000 |publisher=Sheridan House, Inc. |isbn=9781574091199 |editor-last=Mason |editor-first=Charles |location=Davie, Florida |pages=106–7 |language=en |chapter=The spinnaker on a broad reach}}</ref> and, when on a reach or close-hauled, the windward leech of a square sail may be called the luff or the ''weather leech''.{{sfn|King|Hattendorf|Estes|2000|page=283}}{{sfn|King|Hattendorf|Estes|2000|page=271}}{{efn|name=oxford}}
*''Foot''{{anchor|Foot}} – The ''foot'' of a sail is its bottom edge.<ref name="SAIL Magazine 101">{{cite web |title=Know How: Sailing 101 |url=http://www.sailmagazine.com/cruising/cruising-tips/basic-sailing-101/ |work=Sail Magazine |access-date=4 October 2016 |language=en}}</ref> On a fore-and-aft mainsail, the foot is often attached, at the tack and clew, to a [[boom (sailing)|boom]]; on a square sail to a spar by clews on both ends; if no boom or spar is present, the sail is said to be "loose-footed".{{sfn|King|Hattendorf|Estes|2000|page=271}}

====Roach====
A fore-and-aft triangular mainsail achieves a better approximation of a wing form by extending the leech aft, beyond the line between the head and clew in an arc called the ''roach'',{{anchor|Roach}} rather than having a triangular shape. This added area would flutter in the wind and not contribute to the efficient airfoil shape of the sail without the presence of [[Sail batten|battens]].<ref name=Textor/> Offshore cruising mainsails sometimes have a ''hollow leech'' (the inverse of a roach) to obviate the need for battens and their ensuing likelihood of [[Chafing (nautical)|chafing]] the sail.<ref name = Nicolson/>

''Roach'' is a term also applied to square sail design—it is the arc of a circle above a straight line from clew to clew at the foot of a square sail, from which sail material is omitted. The greater the departure from the straight line, the greater the "hollow" in the roach.<ref>{{cite book|author=David Steele|url=https://www.hnsa.org/manuals-documents/age-of-sail/the-elements-and-practice-of-rigging-and-seamanship/sail-making-vol-i/|title=The Elements and Practice of Rigging And Seamanship|year=1794|volume=1|page=126}}</ref><ref>{{Cite book |last=McKay |first=John |url=https://books.google.com/books?id=bxLmDwAAQBAJ&dq=%22hollow-footed%22+sail&pg=PA92 |title=Sovereign of the Seas, 1637: A Reconstruction of the Most Powerful Warship of its Day |date=2020-02-28 |publisher=Seaforth Publishing |isbn=978-1-5267-6632-8 |pages=91–2 |language=en}}</ref> The roach allows the foot of the sail to clear stays coming up the mast, as the sails are rotated from side to side.<ref name="Kipping1847"/>