New composites reduce cavitations in giant marine propeller tests

摘要

QinetiQ has recently completed sea trials of a new composite propeller in Falmouth Bay, UK. With a 2.9 metre diameter it is the world's largest propeller. However, despite its immense proportions it weighs significantly less than an equivalent traditional ship's propeller made from nickel aluminium bronze (NAB). The reason - new lightweight composite materials. The propeller has five composite blades bolted and bonded to a NAB hub. The materials used within the composite are commercially available, and it is the development of the right mix of fibres, resin and laminate lay-up that provide the desired mechanical and environmental performance for marine application. The extensive development trials included durability testing in the marine environment, and water uptake and fouling tests. The effects of cavitation, impact and environmental fatigue were also studied.