Sails of Silver now sported the same line-up that had brought it to the height of its success, "Sails of Silver" has often been seen as embodying a different spirit from their classic albums of the 1970s. Prior to "Sails of Silver", the band had always performed songs written by other people, predominantly traditional songs, but also a few 20th century pieces, such as the two Brecht songs on "Storm Force Ten". But on this album they included several songs they had written themselves, including "Let Her Go Down" and "Senior Service". This was the beginning of a trend that continues down to
Forces on sails travel surface—water, ice or land, constant wind velocity and unchanging sail adjustment. The analysis of the forces on sails takes into account the aerodynamic surface force, its centre of effort on a sail, its direction, and its variable distribution over the sail. Modern analysis employs fluid mechanics and aerodynamics airflow calculations for sail design and manufacture, using aeroelasticity models, which combine computational fluid dynamics and structural analysis. Secondary effects pertaining to turbulence and separation of the boundary layer are secondary factors. Computational limitations persist. Theoretical results require empirical confirmation with wind tunnel tests on scale models and full-scale testing of