Impeller for marine waterjet propulsion apparatus

An impeller (22) for a marine waterjet propulsion system has blades (44) that are configured to reduce cavitation, vibration, noise and physical damage to the major components of the propulsion system or host vessel of installation. The leading edge (52) of each blade of the impeller is skewed forwardly over at least the outer 70% of its span, the forward skew being maximum at the tip (56) and being not less than 35° and preferably not less than 50°. The impeller has a blade area ratio of not less than 1.5. The chord lengths of each blade increase progressively from the point of minimum skew to the tip, resulting in reduced loading in the cavitation critical region. A partial or full tip band may be affixed to the blade tips.