Clipper Class
A clipper is a sailing vessel designed for speed, with that priority taking precedence over cargo carrying capacity, or building or operating costs. It is not restricted to any one rig, and 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 deadrise and ends found in the Baltimore Clipper. The second was a hull with a full mid-section and modest deadrise, but sharp ends - 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. As well as a fast hull, a clipper carried a large sail area - 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.
In assessing the hull of a clipper, different maritime historians use different criteria to measure "sharpness". "Sharpness" or "fineness" is explained by comparing a rectangular cuboid with the underwater shape of a vessel's hull. The more material you have 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 of various clippers, but measured drawings or accurate half-models may not exist to calculate either of these figures. An alternative measure of sharpness for hulls of a broadly similar shape is the coefficient of under-deck-tonnage, as used by David MacGregor in comparing tea clippers. This could be calculated from the measurements taken to determine the registered tonnage, and so can be applied to more vessels.
An "extreme clipper" has a hull of great sharpness, as judged either by the prismatic coefficient, the coefficient of under-deck-tonnage or some other technical assessment of hull shape. It is a term that 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 sailer 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.
In assessing the hull of a clipper, different maritime historians use different criteria to measure "sharpness". "Sharpness" or "fineness" is explained by comparing a rectangular cuboid with the underwater shape of a vessel's hull. The more material you have 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 of various clippers, but measured drawings or accurate half-models may not exist to calculate either of these figures. An alternative measure of sharpness for hulls of a broadly similar shape is the coefficient of under-deck-tonnage, as used by David MacGregor in comparing tea clippers. This could be calculated from the measurements taken to determine the registered tonnage, and so can be applied to more vessels.
An "extreme clipper" has a hull of great sharpness, as judged either by the prismatic coefficient, the coefficient of under-deck-tonnage or some other technical assessment of hull shape. It is a term that 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 sailer 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.
