Shafts

Shaft design starts from designing entire shaftline incorporating all the components from the propeller to the gearbox and including the bearings to make the system safe, vibration free and efficient in operation. Shaft alignment calculation and lateral vibration analysis can be of a great help to that as it allows in depth analysis of the shaftline. This assists with the overall design, position and offsets of bearings to be optimised to reduce vibration, especially at certain critical engine speeds.

View the embedded image gallery online at:
http://cjrprop.com/products/shafts#sigProGalleria144d313be3
 

Every shaft size is carefully calculated to be safe in operation during its lifespan. Class shafts complies with specific class rules and IACS requirements. Every sled keyed shaft is also spooned to avoid stress concentration points in the keyway.

 

Manufacturing

Strength and Corrosion Resistance

Most shafts are manufactured with Marinemet 25 as standard, which is stronger and more resilient to corrosion than even surgical stainless steel.  Other materials from 316L up to Super Duplex are available if required.

Generally, materials are sourced from mills specifically chosen by CJR for their quality to meet IACS requirements.

Shaft sizes are available from 30mm up to 180mm diameter and a length of up to 9m.  Note that shafts in excess of 6m are not generally kept in stock by CJR or its stockholders, and lead times can be up to nine months.

Shaft Cell

  • Provides not only the machining of the shafts themselves but the full assembly and inspection of our shaft-line products; from bar to dispatch.
  • We precision machine fully ground high strength marine propeller shafts using 5 axis machine tools that allow single set-up manufacturing which greatly reduces inaccuracy, unnecessary handling and the total number of operations.
  • All shafts leave the works pre-lapped with their respective coupling in order to ensure sound mating taper contact is achieved, which reduces unnecessary fitting time at the vessel.

Shafts can be manufactured for standard tapered keyed connections to: ISO 1:10, SAE 1:16 or BS marine standard 1:12,  as well as keyless tapered 1:30. Any other non-standard taper can also be machined.

 

Accuracy

Every bar from 30 to 180mm in diameter is straightened to a tolerance from 0.005” to 0.02” over a length of up to 9m and 0.005” to 0.01” on taper respectively and is machined in one piece..

This accuracy ensures each shaft is manufactured to deliver vibration free operation.

 

Installation

CJR offers various services and products to assist with the installation of shafts.  These include Shaft Alignment Calculation to assess best bearing positions and offsets, a laser alignment system, a hydraulic coupling pusher/puller for quick and simple keyed coupling and propeller attachment, and Propsmith - a mechanical system for easy propeller fitting and removal.

For keyless hub-shaft connection CJR can offer a complete hydraulic fitting kit including hydraulic pushing nut and hydraulic pump to expand the hub.  

 

Aftersales support

CJR has developed a trials data acquisition system – TrialDAS – for the analysis of boat performance.  This includes vibration monitoring tuned to the shaft and propeller blade passing frequency.  This allows any shaft straightness or mis-alignment problems to be quickly diagnosed without removing the shaft from the boat for inspection.

CJR can replace and retrofit any shaft of any design within the manufacturing range in case of damage.

 

Related Products

Propeller, Keyways, Prop nut, Coupling, Stern tubes, LVA

  • Bearings

    Suitable bearings are required in stern tube and rudder tube assemblies.

  • CJR Propellers

    Every boat is different and the first sign of this difference can be seen in propeller operation.

  • Couplings

    Couplings are the elements that transfer torque from gearbox to the shaft and because of their role they are under strict supervision of class societies.

  • Ducted Propellers / Nozzles

    CJR can offer ducted propellers systems including any type nozzles and impellers under full IACS approval.

  • Rudder Tubes Assemblies

    CJR manufactures rudder tube assemblies designed for hull trough installation to suit stock diameter from 30mm up to 180mm.

  • Rudders

    Rudder profile and sections are carefully selected to specific regime of the flow around sterngear.

  • Shaft Brackets

    Our shaft brackets are designed bespoke to achieve optimum performance in line with every vessel individual requirements.

  • Shaft Seals

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  • Shafts

    Shaft design starts from designing entire shaftline incorporating all the components from the propeller to the gearbox and including the bearings to make the system safe, vibration free and efficient in operation.

  • Stern Tubes / Shaft Logs Assemblies

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  • Tie Bars

    Tie bars connect both rudder tillers on twin rudder boats to simply synchronise them together.

  • Tillers

    Tiller is important part of steering gear which design is covered by strict rules of classification societies when the boat is built under class.

  • Shaft Alignment

    Using laser technology and precision engineering a bespoke shaft alignment tool has been developed to aid the boat builder’s task of accurately fitting and aligning the stern gear.

  • PropSmith

    For the fast, simple and precise installation and removal of propellers, PropSmith is the professionals’ choice.

  • TrialDAS

    TrialDAS is a new data acquisition system specifically tailored for monitoring sea trials. The system is based on rate gyros, GPS, accelerometers and magnetic field sensors to record every movement of the boat.

  • Keyless Hub Hydraulic Kit

    Quick and convenient method of pushing and releasing large propellers or couplings to and from the keyless shaft cone.

  • Hydraulic Propeller / Coupling Pusher / Puller

    Quick and convenient method of pushing and pulling propellers or couplings to and from keyed shaft end.

  • TrialsAPP

  • Quality Policy

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  • Design

    We don’t only make propellers, we analyse entire propulsion system of each boat starting from hull resistance prediction and hull propulsive factors.

  • Pattern Making

    Precise pattern assures high accuracy of final product and it is one of the most important stages in manufacturing process

  • Casting

    CJR's foundry team has the combined benefits of over 150 years experience in the industry.

  • Machining

    CAD/CAM controlled machining of the cast propellers, P brackets and rudders are undertaken to the fine tolerances of their original design

  • Finishing

    Our processes ensure that the geometry of our finished castings is always true and accurate to the original design.

GET IN TOUCH

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CJR Propulsion Ltd
70-72 Quayside Road
Bitterne Manor
Southampton
SO18 1AD
United Kingdom

Tel: +44 (0)23 8022 2032
Fax: +44 (0)23 8021 1832

info@cjrprop.com