Test model 'Raven', 1867.
© Science Museum / Science & Society Picture Library
6 ft model. In the 19th century, two problems of ship hydrodynamics were given particular attention: stability and resistance. William Froude was the person most asociated with fundamental advances in both these areas. He used a steam launch to tow variously sized models of the 'Swan' and the 'Raven' to test resistance, using a dynamometer to record the results. The models were built from his observations on the form of water birds. The sharp-ended 'Raven' was more resistant than the bulbous 'Swan', regardles of scale.