CALM Buoy Spare Parts Supply

The main roller bearing (MRB) is one of the most critical components in a CALM Buoy system. It is the interface between the turntable structure and the hull structure. It allows the buoy’s turntable to weathervane in accordance with the weather conditions found offshore at a specific CALM Buoy marine terminal.

The MRB comprises of three rings which are specifically designed and then forged to withstand the loads which the CALM buoy is subject to under tanker operational condition, as well as during non-operational storm conditions.

Each ring is assembled and rotates with the help of rollers which are precision machined to allow the two interface structures to come together with minimal play, and to ensure the safest operations for the system.

Within the MRB assembly, purpose designed seals are installed to prevent the ingress of water. At the same time, these seals allow the grease used for bearing maintenance to safely pass through the bearing in order to safely maintain the bearing’s longevity.

The MRB sits between the turntable & hull support rings and are assembled with 10.9 grade bolts, which can vary in size from M36 to M42 depending on the buoy’s design.

Monobuoy can design and supply complete bearing packages which include all items required to replace or retrofit these bearings onto existing buoys, as well as the tools (tensioner, bridge connector, hydraulic pump and connecting hoses) required to safely install and tension the bolts to the pre-defined requirements.
Main Roller/Slewing Bearing
Main Roller Bearing
 Chainstopper Assemblies
The chainstopper assemblies on a CALM Buoy are the connection points between the buoy’s hull structure and the subsea chainlegs which are used to anchor the buoy to the seabed.
The number of chainstoppers varies from buoy to buoy, but is generally 6 or 8 leg systems.

There are typically two types of assemblies:
Rock and Roll chainstoppers
Trunnion and bush chainstoppers

There are also two types of clamping methods for each type of chainstopper:
Cone Type
Ratchet Type

Nowadays, the ratchet type method is the more popular design, as it is easier and safer to use during buoy installation and maintenance operations. This has meant that the cone type chainstopper has pretty much been phased out. However it remains on some old systems.

Monobuoy has worked with all types of chainstoppers and has taken this experience to design and build its own chainstopper assembly which can be used or retrofitted onto existing CALM Buoy systems.
Chainstopper Rock and Roll Type
Mooring Bridle
The water barrage and bearing protection system protects the main roller bearing from direct exposure to the marine environment (marine spray, overtopping waves etc.). The assembly is designed to allow easy offshore installation and maintenance. It is also designed to allow access to the main roller bearing. This can be required if the bearing needs to be inspected visually or if grease samples need to be taken for further analysis.
Bolt tensioning checks which are required as part of the regular maintenance of every CALM Buoy system can also be performed if required.

The assembly is composed of GRP covers and a stainless steel latching system. It is then seals off using large diameter lip seals that cover the entire diameter of the assembly.
Monobuoy can adapt its design to be retrofitted onto existing CALM Buoy systems.

If required, Monobuoy can also supply individual components that need replacing on existing water barrage & bearing protection systems (Rubber Lip Seals, Stainless steel latches, GRP Covers, bolting arrangement etc.).
Water Barrage and Bearing Protection System
Water Barrage System Open GRP Cover
The greasing system on a buoy is a maintenance aid that helps the user/operator perform daily/weekly/monthly greasing activities on a buoy in order to maintain the buoys critical mechanical items in good condition.

It is composed of grease distributor blocks that allow the user to define a specific amount of grease is distributed uniformly across the main roller bearing for example. It is also used to distribute grease through the central pipe unit bearing. These distributor blocks are connected to each bearings grease connection points using SS316 tubing and Parker/Swagelock fittings. This is then linked to a central grease reservoir which can be pumped manually or automatically using onboard hydraulic or pneumatic pumps.
Greasing System
Grease Distributor Block
On Board Piping Valves and Expansion Pieces

 The valves on a CALM Buoy are located on the turntable and centrewell pipe run sections. They are used to control the flow of product through the buoys’ piping system, and can be used for various other maintenance tasks such as flushing, maintenance or shutdown activities.

The expansion joints on a buoy are located on the turntable piping, near the central pipe/ swivel unit outlets and allow the stresses and loads generated from the rotational forces of the buoy to be absorbed.

The rubber expansion joints & backing flanges allow a pre defined deformation to take place when the buoy is under load.
 Expansion Piece
Navigational Aids
Monobuoy can supply the following navigational aids for CALM Buoy systems:

Marine Lights
Radar Reflector
Fog Horn
Solar Panels

Anchor systems
Monobuoy can define and supply the items for CALM Buoy anchoring systems such as pile design and fabrication, design and supply of anchor, anchor chain, chain connectors (H-links, joining & anchor shackles), chainstopper assemblies, design and supply of clump weights & drape chain.
Monobuoy can define and supply the following items for CALM Buoy hose systems:

Subsea hose configurations (Lazy S, Steep S, Chinese Lantern)
Floating hose configurations (tanker range 1000DWT to 400,000DWT)
Mooring hawser system
Monobuoy can supply miscellaneous items for CALM Buoy systems such as bolting arrangements, seal/gasket arrangements, paint system for (emerged/submerged/compartment) zones, EP2 Type Grease for main roller and CPU bearings, turntable locking devices, safety equipment (life buoy, life extinguisher in a box), cathodic protection (anodes and bolting arrangements), boat landing rubber fender.

If you require any CALM Buoy spare parts please contact our team through our
Solar Panel and Marine Light
Turntable Butterfly Valves
Floating Hose
Hose and Hawser Systems

Designing and Building Single Point Mooring Systems

 Mooring Bridle Assemblies
The mooring bridle assembly on a CALM Buoy is the connection point between the buoy turntable mooring platform and the loading/offloading tanker via means of a mooring hawser.
It may have various configurations, but the most common type is a dual triplate assembly which is held together by a load pin.

The buoy connection side is done via several links of chain, end links and joining shackles that are connected straight onto the turntable structures two high strength mooring lugs. Whereas the hawser side is simply connected through an adaptation link which is then connected straight onto the thimble on the hawser assembly.The bridle assembly is designed to withstand loads from tankers of up to 400,000DWT. The mooring lugs and bushes are incorporated into the turntable structure to enable the loads generated by tankers to be equally distributed through the turntable structure and more specifically into the main roller bearing assembly.

Monobuoy can design and supply different types of bridle assemblies to suit clients specific mooring platform designs.

Monobuoy can also offer individual components such as load monitoring pins, joining shackles or tri plates in order to be incorporate into existing designs.

This allows clients to replace individual parts rather than full assemblies which can be more costly and time consuming.
Bearing Construction