• Standard XL Propeller Shaft Bearings
• Rudder Bearings
• Composite Bearings
• Compac Bearings
• New Thorplas Thermoplastic Bearing

XL Propeller Shaft Bearings - are available in a full range of shafts from 3/4" to 40". These bearings have their water grooves moulded in. They are designed as direct replacements for bronze/rubber Cutless type bearings. XL Propeller shaft bearings are available fully-finished, ready to install, and semi-finished for machining to suit specific shaft and housing dimensions. Semi-finished bearings are designed with a small amount of extra material on the inside and outside so that they can be machined to accommodate minor variations in shaft and housing dimensions.

Rudder Bearings are available in tubular form up to 40" diameter in either XL of SXL grades. Thordon rudder bearings have provided superior performance to conventional materials such as bronze of phenolic resins in VLCC's, bulk carriers, container ships, and many other types of vessels. SXL is the recommended grade if the bearings will run dry under certain vessel loading conditions, of if design pressure is more than 
500 psi. (3.45 N/mm²)

Composite Bearings are especially designed for extremely dirty conditions such as river boat propeller shafts and suction cutter head bearings on dredges. Composite bearings have proven their ability to last at least twice as long as any conventional bearing material in the worst operating conditions. Thordon Composite Bearings have proven their value on some of the world's largest dredges, and on tugs or tow boats in silt laden rivers such as the Rhine and Moselle in Europe, and the Mississippi in the USA.

Compac Bearings - Thordon Bearings Inc. research department spent several years studying propeller shaft bearing design for water lubricated operations. The result was Compac. Compac features a length diameter ratio of 2:1, half of the standard bearing length. It also features the low friction SXL grade, and special groove design with no grooves on the bottom for better hydrodynamic film generation. The result is a cost effective bearing with significant low friction performance advantages. Builders of sport and racing boats around the world are beginning to specify Compac because of its unique low friction advantages.

Developed in the 1960's as a high performance pump bearing, Thordon is an elastomeric polymer alloy that provides exceptional wear life, particularly in abrasive operating conditions. Thordon's proven performance in vertical pumps led to its very successful adaptation as a propeller shaft bearing.

Thordon Bearings, offers a choice of either sealed or open, water lubricated propeller shaft bearing systems. Thordon's open, water lubricated system choices are Compac, XL and composite; each offering specific advantages in different water environments.

Thordon's grease-free rudder bearing systems are operating smoothly and pollution-free on thousands of vessels around the world. Using proven Thordon SXL bearings, the system offers the reliability needed in today's marine industry and is backed by Thordon's exclusive 10 year wear life guarantee.

Today, with over 25 years of trouble-free installations documented, Thordon marine bearing systems are the proven, reliable, pollution-free solution for ship owners, managers, and yards who demand the best.   

Strong Naval Performance Continues

Blohm & Voss GmbH of Hamburg, Germany has recently ordered Thordon COMPAC water lubricated propeller shaft bearings for a number of MEKO frigates they are currently contracted to build. COMPAC bearings have been supplied to many Navies worldwide with impressive wear results.

Recent data in from Canadian Navy Patrol Frigate Montreal indicates total average bearing wear of 0.76 mm (0.030") in just over 9 years of operation.

Thordon COMPAC bearings were specified by the Canadian Navy in 1992 after problem with the rubber stave bearings originally specified for the 12 ship project were encountered during sea trials. COMPAC successfully met the Navy's strict acoustic and friction requirements and the Navy report that they continue to be quite happy with Thordon's performance on all 12 ships over the past 10 years.

Compac bearings installed on Canadian Patrol Frigate

Compac bearings with single key design supplied to Blohm & Voss, Germany

Largest Sloop Ever Uses Thordon

Because of the vessel's size, much of the machinery and many of the fittings of the yacht have been developed uniquely for Mirabella V. One of the biggest production challenges was the custom built retractable keel designed by Ron Holland Design of Ireland. The keel weighs 150 tonnes (330,600 lbs) with a 6m (20ft) reach and is raised by a powerful hydraulics in order to reduce the vessel's draught. The seven minute cycle to hoist the keel to its up position reduces the draft to 4m (13 ft) allowing the vessel to go anywhere a 25m (80ft) race boat can go. "The vertical lift keel was totally different than the swing keels, traditionally used in this application", says John Stott, Naval Architect with Ron Holland Design. "In order to design the keel support pads, we searched for materials that had very specific requirements, specifically high load carrying capability and good wear resistance," says Stott. After reviewing some composite materials, Stott discovered Thordon and made contact with Thordon's Chief Design Engineer, Dr. Keith Laskey.

"Dr Laskey supplied me with some possible approaches for the design methodology of these pads which were very helpful," says Stott. Given the bearing pressure design criteria, Thordon SXL wear pads were specified for the lateral guide components of the keel, as well as Thordon SXL bearings for the front and back guide components.

After the initial design work of the keel was passed on to Vosper Thornycraft, the builder reviewed more bearing applications with Thordon's distributor in UK, Stephenson Engineering. This led to specifications for Thordon SXL TRAXL bearings including Thorseal, a self lubricating polymer lip seal, for the location ram bearings in the keel locking arrangement.

"SXL and TRAXL is able to withstand high operating  pressures and absorb impact making them more resistant to damage than stiffer bearings and the Thorseal internal lubricants reduce the cylinder wear", says Chris Beech, Sales Manager of Stephenson.

Beech added, "Noise was also a concern for Vosper when the 150 tonne keel is raised and lowered. Since Thordon dampens and reduces operating noise compared to metals, the guests aboard Mirabella V won't hear any sliding metal noises, when that keel moves up and down."

Mirabella V has been designed for performance, ocean going voyaging. Her sail inventory includes the world's largest sail - a 1,900m² (20,450ft²) reacher. She can, however, in addition to power at 16knots with her twin MTU's driving the 1.5m (5ft) KaMeWa Ulstein XF5 controllable pitch propellers. The propulsion system supplier, Rolls-Royce KaMeWa, specified Thordon's water lubricated COMPAC propeller shaft bearings making Thordon's oil and grease - free bearings quite prevalent throughout the dynamic vessel. Delivery of Mirabella V is scheduled for Winter 2003.