It is 39 years since sea trials of the first hovercraft. Hovercraft are a new means of transportation, and so machinery, equipment and structural materials have had to be adapted for successful use in their special operating environment, which differs from that in aviation and for other marine vessels.
A somewhat difficult technical and economic path has been negotiated by the developers of hovercraft technology to date. Currently about 2000 craft are in operation for commercial water transportation, recreation, utility purposes and military applications around the world. They have taken a key role for a number of military missions, and provide utility transportation in a number of applications which are quite unique.
Hovercraft in China have developed from prototype tests in the 1960s, to practical use as ferries and military craft. More than 60 hovercraft types have been constructed or imported for operation in China. This book has been written to summarize the experience in air cushion technology in China and abroad to date, with the aim of improving understanding of air cushion technology.
Due to the relatively quick development of the cushion technology relative to other water transportation, the theories and design methods applied to hovercraft design and operations are continuing to develop at present. For instance various quasi-static theories of the air jet cushion were derived in the 1960s, but once the flexible skirt was developed, the hydrodynamic and aerodynamic forces acting on hovercraft changed so significantly that these earlier theories and formulae could not continue to serve in practice.
The theory of air cushion performance has therefore changed significantly since the 1960s. On one hand a lot of technical references and some technical summaries and handbooks with respect to air cushion technology are available to translate the physical phenomena but on the other, owing to different research methods, objects and means, there are many different methods which suggest how to deal with such theories.
So far no finalized rules and regulations for hovercraft construction can be stated.
In addition regulatory documents concerned with stability, seaworthiness and the calculation methods determining the static and dynamic deformation have not reached public literature.
The aim in writing this book has been to summarize the technical experience, both in China and abroad, to systematically describe the theory and design of hovercraft, and endeavour to connect the theories with practice in order to solve practical problems in hovercraft design.