Quick Release Mooring

PODx emergency mooring release

Typical applications
Typical protection scenarios
Features and benefits
How it works
Specifications

Emergency to safety in 100 milliseconds

mooring release

The quick and safe mooring/towing hawser release

The PODx mooring or towing hawser release delivers quick and safe disconnection of FSO/FPSO and conventional tankers moorings in emergency situations.

The Gall Thomson PODx (Powered Offshore Disconnect) provides an identified parting point to an offshore mooring line when an emergency situation is anticipated.

The PODx remote activation facility enables control over emergency situations and enables a new level in the protection of people, assets, operations and reputations against offshore emergency situations.

The PODx mooring release is proven technology with an impressive track record of in-field application and reliable activations delivered exactly when required.

PODx can be retrofitted into existing deck configurations without hot work/extensive fixturing.

PODx presents a more efficient and effective alternative to other equipment, practices and procedures in the industry.


PODx is designed to exceed offshore operational requirements while meeting OCIMF safety guidelines.

  • Simple commissioning and installation – no adapter plate is required.
  • Low maintenance.
  • Offshore proven track record.
  • Simple release bolt mechanism – no axles, shafts, hubs or bearings to seize.
  • Sealed internals until an activation occurs.
  • Minimal footprint – compact design – low weight
  • Fits between two shackles.
  • Load monitoring system available.
  • Dynamic release bolt load rating that can be varied to suit the system.
  • Re-usable.
  • Long lifespan.
  • Versatile installation – including retrofit.
  • OCIMF Compliant.

podx emergency mooring release


Typical applications

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PODx delivers a new level in safety and emergency management for a wide range of offshore applications including:

  • FPSO/FLNG tandem mooring release hawser including hawser reel application.
  • FPSO/FLNG heading control.
  • FPSO/FLNG station keeping.
  • Emergency towing.
  • Rig/FPSO/FLNG towing.
  • Anchor Handling Tug operations.
  • Oil tankers.
  • Chemical tankers.
  • LPG tankers.
  • LNG Carrier.
  • FSRUs.
  • Port/Jetty applications.
  • Catenary Anchor Leg Mooring (CALM) buoy applications.
  • Conventional Buoy Mooring (CBM)/Multi Buoy Mooring (MBM) applications.

Typical protection scenarios

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FPSO tandem mooring configurations

Mooring hawser may have to be released in an emergency to prevent collision between the conventional tanker and the FPSO.

This may occur due to bad weather, swells, malfunctioning equipment or any of many other foreseen and unforeseen situations and causes.


FPSO heading control and positioning

Release of the mooring hawser may be required in a safe and controlled manner during a potential high risk procedure such as heading control or positioning operations.

FPSO heading control:

When a maintenance team needs to carry out inspections on the FPSO subsea, the FPSO must be kept in a certain heading using an Anchor Handling Tug (AHT) for several hours or days.

A mooring line is connected between the AHT and the SMIT bracket located on the FPSO.

Feedback from Master Mariners and Asset Managers highlights the risks of emergency disconnection of the mooring line using the following procedures:

  • Option 1: From the AHT, a person will have to cut the mooring line under tension with an axe.
  • Option 2: An operator on board the FPSO will have to remove a pin from the SMIT bracket to release the mooring chain under tension.

Both options are not safe for AHT/FPSO personnel.

PODx presents a perfect retrofittable mooring release option for temporary use during heading control operation.

FPSO station keeping:

During a FPSO station keeping operation, the FPSO is kept in specific position offshore during commissioning/hook up operations with Anchor Handling Tugs until the operation is complete.

As with FPSO heading control operations, emergency disconnection of the mooring line between the FPSO and the AHT often depends on high risk practices that can easily be made safe with the simple retrofit of PODx.

The PODx activation will release the mooring hawser immediately and minimise risk to personnel and structures.


Features and benefits

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Economical

PODx is extremely economical compared to other available devices.

Proven track record

PODx offers a proven track record in excess of 20 years in several FPSO tandem mooring and FPSO main mooring applications.

PODx has been designed to stringent FPSO contractor and operator requirements.

PODx is OCIMF Compliant.

podx mooring release infield

Shown: Example of PODx in service

Easy resetting after activation

With no additional parts or service procedures required, PODx can be reset and reused quickly and efficiently on board the FPSO/AHT using standard tools: this can be done with or without the assistance of Gall Thomson.

Easy install and commissioning

PODx is simply installed between two shackles and no hot work or extensive drilling or fixing is required.

PODx can therefore be quickly fitted offshore when the FPSO or vessel is in the producing field.

PODx can also be retrofitted for permanent applications or for temporary short-term use.

Easy maintenance and operational monitoring

PODx offers minimum offshore maintenance and routine monitoring. The simple but ingenious design of PODx delivers extremely reliable performance and a long maintenance-free period of typically 36 months.

Lifespan of 25 years

The main components of PODx have an expected design life of 25 years.

Minimum deck footprint

Due to its compact and simple design, PODx offers a minimum footprint on FPSO and vessel decks. This is a major operational advantage over many alternatives.

Reliable

The PODx block is designed to enable the link to be released reliably at tensile loads above the yield point of the shackles in an emergency.

Robust

The PODx release bolt is enclosed within blocks. This makes the whole assembly very robust and suitable for the rigours of offshore operations.

No complicated monitoring system

The PODx is safe and simple to use. It can be supplied with a load monitoring shackle if required but is not supplied with an extensive load monitoring system.


How it works

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Unique design delivering improved operational efficiency

PODx is proven in service around the world in a number of FPSO applications and it is the only design in the world that uses a release and in-situ resettable bolt.

The release bolt will separate on demand; allowing the link to reliably release in under 10 ms at tensile loads above the yield point of the shackles.

This release bolt is isolated by two blocks and has no moving parts until a mooring release is activated. This means PODx is extremely reliable and operationally friendly.

The patented design of the resettable release bolt sees only 13% of the maximum tensile load at any one time.

The design of the resetting bolt is carried out in accordance with offshore loading conditions – taking into account safe working load in relation to the dead weight tonnage.


mooring emergency release closed mooring emergency release activated
PODx in set (closed) position PODx in activated (open) position

Remote operation for maximum safety and control

PODx is activated using the Reflex HPU (R-HPU) which is located at a safe and convenient distance from where the mooring is released.

The Reflex R-HPU is a compact, pre-charged and low maintenance unit and provides a rapid hydraulic signal to PODx.

The HPU can be operated from a simple panel via pneumatic or electrical push buttons. This uses a stringent release sequence and is also equipped with mechanical interlocks to prevent accidental activation.

The integral control valve self-relieves the control lines. This compensates for temperature fluctuations, while retaining hydraulic pressure stored within accumulators when in the dormant state.

Manual backup option

PODx can also be activated with a simple manual hand pump in case of complete FPSO/vessel blackout.

Safe release

The safety factor built in PODx is 5:1 and PODx includes a series of safety interlocks. This ensures unintentional release is impossible.


Specifications

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  1. Purpose built HPU supplied as standard.
  2. PODx supplied with shackles.
  3. Load monitoring shackle (optional).
  4. Resetting bolt (optional).

The release bolt is specified to the meet the requirements of the application.

The release bolts offer a safe working load rating from 2.5 tons to 350 tons.
Higher release bolt ratings are available on request.

Material

Main body components: Offshore grade steel.
Release Bolt: High grade stainless steel that is rated, tested and certified.

Extensive testing of materials, combined with many years of field experience, ensures performance integrity and reliability in all environmental conditions.