Architectura Navalis Mercatoria
By Fredrik Henrik af Chapman, Dover Books, 2006, ISBN 0486451550, 160 pp., 31 X 23.7 cms, Paperbound £15.99
Fredrik Henrik af Chapman (1721-1808) was born of English parents in Sweden. He followed his father into the Swedish royal shipyard. As a junior shipwright he found contemporary shipbuilding frustrating. It was still a matter of trial-and-error building on experience accumulated over millennia. Ship stability could not be reliably predicted; the trauma of the disastrous capsizing of the Wasa still haunted builders. Legal requirements encouraged cautious design. Shipwrights could not determine the volumes of spaces for cargoes or stores or ships' displacement. Performance could not be predicted accurately.
Chapman saw that the mathematics and physics emerging in Europe suggested some solutions. In his thirties he went abroad to study, first with Thomas Simpson in London, and then in Paris where he studied the work of Leonard Euler and Pierre Bouguer.
Chapman returned to Sweden in 1757, where he applied his principles to designs for galleases and gunsloops for the Finnish archipelago fleet that was being built up to counter the constant threat from Russia. The prototype of one of Chapman’s gunsloops, with removable guns capable of being landed in what today would be called commando operations, was demonstrated to King Gustav III. The king joined the trial as oarsman-gunner and was so impressed that he made Chapman a lieutenant colonel on the spot. By the 1780s Chapman was in command of the royal shipyard at Karlskrona. Reorganising the yard’s layout and work methods, including the introduction of prefabricated production, he was able to reduce the build time of ships of the line from a year or more to eight weeks. He produced twenty major warships in the three years from 1782-85, a rate not surpassed until prefabricated construction was reintroduced in World War II Liberty ships. Chapman also constructed merchant ships in civil yards. Chapman’s application of science and his use of models in experimental tanks led to more reliable ship designs. Innovation was no longer discouraged. He published his conclusions in Architectura Navalis Mercatoria (1768) and the Tractat om Skepps-Byggeriet (Treatise on Shipbuilding), of 1775. These are the classics that laid the foundation of modern naval architecture. The present work is Dover Books’s republication of both.
Architectura Navalis Mercatoria includes Chapman’s Index in English. It has 60 plates of his meticulous and beautiful line drawings of the hulls of some 70 vessels, large and small, merchantmen and, notwithstanding the title, of warships. Each plate has scales in Swedish, English and French measures. One other plate shows the French, the English and the Dutch methods of launching ships, and another the rigs common in northern Europe.
The twenty-five page Tractat om Skepps-Byggeriet (Treatise on Shipbuilding) is in James Inman’s English translation of 1820. It gives Chapman’s formulae to calculate cargo-hold volume, stability, hull resistance to water, and good sailing qualities. Chapman warns that ship behaviour, nevertheless, will always have a degree of unpredictability.
Hats off to Dover for making Chapman accessible in such a splendid book! It is a volume of considerable beauty that will give much aesthetic pleasure. It will also be valued for its practical content by historians and by model makers. Two minor criticisms: the tight binding makes Chapman’s index difficult to use and impossible to search (I made a searchable spreadsheet version); also it is a pity that Dover’s editorial team has not been credited.
Reviewed by David Jenkinson
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