The Axiom propeller - 15 years in development

“… the interaction of the water, propeller and hull with each other are so complex that no one understands exactly what is happening …” The Propeller Handbook, David Gerr.

The quest to design a new propeller was not simply an exercise in how to break with tradition and spark controversy. The primary motivation was derived from a desire to make rescue boats perform better, both for the crew and the casualty. After 15 years of development we are, admittedly, still working on this.

Research originally began after a slow, rough trip back to the UK from Holland in an ex-RNLI Rother Class boat. A greater knowledge of the dynamics of marine propulsion, and more generally the conventional marine screw, was obtained from numerous textbooks on propellers and related subjects (fluid mechanics, naval architecture etc). However, it proved invaluable to be able to test repeatedly on a known boat with marine screws ranging in quality from average to good, measuring all manner of variables including speed, RPM, exhaust gas temperature, slump, wake etc. These tests established targets for performance when development of a new blade shape began. Where we started is difficult to recall but over time with much trial and error, the unique Axiom blade shape evolved. Eventually we reached a point where we were confident enough to invite independent trials of the propeller. Certain that the Axiom was complete, we set about consolidating the design and full patent was awarded in June 2009.