CJR Propulsion is celebrating 10 years since designing and manufacturing their first flow-aligned rudder system.
Technical Sales Director, Alex Stevens, explains: “Back in 2014, this technology, also referred to as twisted rudders, was only being utilised by larger ships to improve efficiency. However, when a customer told us they needed help to achieve a very tight contract speed, we decided to put the concept to the test on their smaller vessel.
“The results spoke for themselves and over the last 10 years we’ve honed our flow-aligned capabilities by investing in our own in-house software and other manufacturing upgrades. We’ve now supplied hundreds of our bespoke designed flow-aligned rudders to a wide range of vessels of all sizes, from work boats and ferries to super yachts and competition sport fishing vessels.”
How does it work?
Although traditionally motor yacht rudders have a straight surface area, they operate in a position of uneven water flow directly behind the propellers. As a result, a suction pressure peak can form at or near the leading edge of the rudder. CJR accurately simulate these forces and can predict how they would impact the propulsion system’s performance. With this comprehensive understanding, we’re able to design and craft a rudder blade with a unique ‘twisted’ profile – one which is perfectly aligned with the propeller flow angles along the entire span.
Here are just some of the benefits of choosing a CJR flow-aligned rudder:
– Up to 2kts increase in speed compared to top straight rudders.
– Optimised profile of each rudder delivered through CFD.
– Significantly improved propulsive efficiency, with no impact on vessel manoeuvrability or steering performance.
– Reduced rotational losses and minimised drag provide the potential to increase top speed by up to two knots.
– Power savings provide the opportunity to reduce engine load by up to 3% at the same RPM, in turn significantly reducing fuel burn.
– Lower suction pressure peaks to reduce cavitation, noise and vibration, improve both ride comfort and rudder lifespan.
– Potential to downsize the steering rams to save weight and cost.
– Manufactured to any classification society rules, including all IACS societies.
Get in touch to find out more: alex@cjrprop.com
