TOP OF THE PROPS

Hugo Andreae takes a look at a revolutionary new propeller said to be faster and more efficient than rivals

- Hugo Andreae

A radical new tipless propeller is being touted as the single biggest advance in propeller design since the 1930s.

Claimed to deliver significant fuel savings across all different types and sizes of craft as well as faster planing, higher top speeds, superior handling and reduced vibration, it sounds almost too good to be true. However, extensive sea trials carried out by US website boatest.com on the new Sharrow Propeller MX-1 seem to confirm all of the above and show efficiency gains of between 9-15% over comparable 3-blade propeller designs.

The tests were carried out on a 20ft Bayliner VR5 sportsboat fitted with a standard Mercury 150hp outboard engine, comparing Sharrow’s new tipless MX-1 against two market leadingcompetitors. Not only was it the fastest of the three (41.7 knots vs 40.8 knots and 39.0 knots) and the most efficient (4.6mpg @ 32 knots vs 4.2mpg and 4.1mph), it also planed earlier and outperformed them both at every 500rpm increment from idle speed to wide open throttle. This is crucial, as propellers which are designed to give the highest possible top speed often struggle at low to medium revs, and vice versa. So how is Sharrow Engineering claiming to have cracked the conundrum that has stymied so many others?

TIP TROUBLES