Editing Clipper (section)

==Definitions==
[[File:Clipper barque Spirit of the Age, PY0633.jpg|thumb|Clipper barque ''Spirit of the Age'' 1854 by [[Thomas Goldsworthy Dutton|T. G. Dutton]]]]
A clipper is a sailing vessel designed for speed, a priority that takes precedence over cargo-carrying capacity or building or operating costs. It is not restricted to any one rig (while many were fully rigged ships, others were barques, brigs, or schooners), nor was the term restricted to any one hull type. Howard Chapelle lists three basic hull types for clippers. The first was characterised by the sharp {{nautical term|deadrise}} and ends found in the Baltimore clipper. The second was a hull with a full midsection and modest deadrise, but sharp ends{{snd}}this was a development of the hull form of transatlantic packets. The third was more experimental, with deadrise and sharpness being balanced against the need to carry a profitable quantity of cargo. A clipper carried a large sail area and a fast hull; by the standards of any other type of sailing ship, a clipper was greatly over-canvassed. The last defining feature of a clipper, in the view of maritime historian David MacGregor, was a captain who had the courage, skill, and determination to get the fastest speed possible out of her.{{r|MacGregor 1993|pp=16–21}}{{r|Chapelle 1967|pp=321–322}}

{{anchor|fineness}}In assessing the hull of a clipper, different maritime historians use different criteria to measure "sharpness", "fine lines" or "fineness", a concept which is explained by comparing a [[rectangular cuboid]] with the underwater shape of a vessel's hull. The more material one has to carve off the cuboid to achieve the hull shape, the sharper the hull. Ideally, a maritime historian would be able to look at either the block coefficient of fineness or the prismatic coefficient{{efn|The block coefficient of fineness is a mathematical measure of sharpness used by naval architects, which compares the hull with a hypothetical block equal in length, breadth, and height to the immersed part of the hull. The prismatic coefficient makes a similar comparison to a prism with the immersed hull's dimensions, and is considered to the best indicator of potential speed. The lower the coefficient, the more material has to be removed from the hypothetical cuboid. Many commercial sailing vessels are unlikely to have had a prismatic coefficient less than 0.57.}} of various clippers, but measured drawings or accurate half models may not exist to calculate either of these figures.<ref name="Chapelle 1967">{{cite book |last1=Chapelle |first1=Howard I. |author1-link=Howard I. Chapelle |title=The Search for Speed Under Sail, 1700–1855 |date=1967 |publisher=Bonanza Books}}</ref>{{rp|pages=43–45}} An alternative measure of sharpness for hulls of a broadly similar shape is the coefficient of underdeck tonnage, as used by David MacGregor in comparing tea clippers. This could be calculated from the measurements taken to determine the registered tonnage, so can be applied to more vessels.{{r|MacGregor 1983|pp=87–88}}

An [[extreme clipper]] has a hull of great fineness, as judged either by the prismatic coefficient, the coefficient of underdeck tonnage, or some other technical assessment of hull shape. This term has been misapplied in the past, without reference to hull shape. As commercial vessels, these are totally reliant on speed to generate a profit for their owners, as their sharpness limits their cargo-carrying capacity.

A [[medium clipper]] has a cargo-carrying hull that has some sharpness. In the right conditions and with a capable captain, some of these achieved notable quick passages. They were also able to pay their way when the high freight rates often paid to a fast sailing ship were not available (in a fluctuating market).

The term "clipper" applied to vessels between these two categories. They often made passages as fast as extreme clippers, but had less difficulty in making a living when freight rates were lower.{{r|MacGregor 1993|p=16}}