CJR delivers


The results from the sea trials were even better than expected, with a one-knot speed increase and notably smoother operation – all attributed to CJR’s propellers.

Couach celebrated 120 years of operation in 2017. The French motoryacht builder marked the occasion with the completion of two new motor yacht projects, including the fifth unit of its 2300 FLY motor yacht series, which was launched in March with a pair of CJR Propulsion CNC-machined Class S propellers.

The fully bespoke, fast-planing vessel, which has been built for a first-time owner, features CJR’s MRKRevolution propellers, zero-speed gyro stabilisers and twin MAN 12V 1400 diesel engines, to produce a displacement of 50 tonnes when fully loaded.

CJR’s relationship with Couach began when the Gascony-based yard got in touch to understand the difference CJR’s Class S propellers could make to the vessel’s performance, as Simon Lewis, Head of Propeller Design for CJR Propulsion explains:

“Our reputation for delivering peak performance means clients come to us with a list of areas where improvements can potentially be made. Sometimes there is a specific issue but, more often, the builder is simply looking to offer the very best product they can – as was the case for this project. The Couach 2300 Fly was already known for its elegant lines and excellent seakeeping but Couach wanted to understand if our technical approach could help increase ride comfort and potentially deliver improved top-end speed. Following our unique design process, the propellers for the 2300 Fly were cast in our foundry and finished using our five-axis CNC machine to produce an end result that matches the CAD design to a very high tolerance. This level of precision throughout the design and manufacture process is key to delivering improved performance, but the effort is not worth anything if we’re unable to qualify the improvements we’ve made with tangible data.”

With this in mind, once the propulsion system was installed, CJR performed extensive sea trials using its TrialsApp data acquisition and analysis tool. The TrialsApp system, which was developed in-house, consists of a lightweight, 10” android tablet PC, running bespoke application software that collects data from on-board sensors, as well as a range of wireless sensors, and provides an extensive report covering speed, vibration, noise levels, shaft RPM, trim, and roll. The results from the sea trials were even better than expected, with a one-knot speed increase and notably smoother operation – all attributed to CJR’s propellers.

Couach’s mechanical systems manager, Rémy Barbedroite, commented on the trial results adding: “One of the most attractive things about the 2300 model is its suitability for owner-operators who want to spend their time aboard in complete privacy, without the need for a crew. Part of that experience is enjoying a smooth ride when you’re at the helm – feeling only the speed and excitement. CJR’s involvement on the latest 2300 Fly has helped deliver that, with less residual vibration across the speed envelope, better top-end speed and increased power efficiency – which helps reduce fuel consumption at cruise speeds. Overall, we were very impressed by CJR’s professionalism and commitment to getting everything right first time and the results of the trials confirmed all CJR’s predictions – further demonstrating that their approach works.”