Protection Status Guide

Protection status guide for offshore crude oil transfer operations


Assessments are based on typical configurations and Gall Thomson field operation experience.

Status may be different depending on operational and environmental circumstances. It is recommended to contact the Gall Thomson Technical Team before assuming the estimated protection status of any specific operation or operational environment.

Protection status categories are designed to manage risk reduction and are based only on Gall Thomson products, specifications, procedures and services.

Protection estimates assume application, management and servicing of equipment within Gall Thomson Installation Operations Manual (IOM) and Gall Thomson Approved Certification (GTAC) guidelines.

Last updated 1 September 2021


Emergency scenarios

Scenario Set 1

Sudden tanker breakout due to:
Tanker mis-manoeuvring.
Failure of deck equipment.
Strong current.
Sudden storm.
Underwater current – soliton.
Accidental pull by support tug.
Variable tides.
Where applicable Tanker colliding with SPM.

Surge pressure due to:
Failure and closure of Butterfly Valve in full flow.
Failure of North Sea Valve in full flow.
Accidental tanker manifold valve closure in full flow by tanker crew.
(When designed into the MBC specification.)

Protection measure: passive (automatic) activation (Gall Thomson Marine Breakaway Coupling – MBC)


Scenario Set 2

Anticipated emergency due to:
Manageable hawser failure.
Ship event such as fire.
Approaching storm.
Known approaching vessel malfunction or failure.
Engine or rudder issue.
Electrical issue affecting dynamic vessel positioning.
Electronic issue affecting dynamic vessel positioning.
Software issue affecting dynamic vessel positioning.

Protection measure: active (procedural) release (Gall Thomson Protected Transfer System – PTX)


Scenario Set 3

SPM/Tanker collision
Tanker mis-manoeuvring due to:
Human or equipment error.
Strong current.
Sudden storm.
Underwater current – soliton.

Protection measure: passive (automatic) activation (Gall Thomson Underbuoy Breakaway Coupling – UBC)


Status protections by application


PROTECTION STATUS A: Operational Protection. Protected in foreseen circumstances.


STS Crude Oil Operation
Configuration: PTX installed.

gall thomson tanker sts ptx

Protected
Scenario Set 2

Not applicable
Scenario Set 1
Scenario Set 3


FPSO/FSO Tandem Offloading Operation
Configuration: MBC and PTX installed.

Protected
Scenario Set 1
Scenario Set 2

Not applicable
Scenario Set 3


SPM operation
Configuration: UBC, MBC and PTX installed.

gall thomson spm ubc mbc ptx

Protected
Scenario Set 1
Scenario Set 2
Scenario Set 3

Unprotected
None identified


PROTECTION STATUS B: Operational Protection. Protected in many but not all foreseen circumstances.


FPSO/FSO Tandem Offloading Operation
Configuration: MBC installed. PTX not installed.

gall thomson fpso mbc

Protected
Scenario Set 1

Unprotected
Scenario Set 2

Not applicable
Scenario Set 3


SPM operation
Configuration: MBC and PTX installed. UBC not installed.

gall thomson spm mbc ptx

Protected
Scenario Set 1
Scenario Set 2

Unprotected
Scenario Set 3


SPM operation
Configuration: UBC and MBC installed. PTX not installed.

gall thomson spm ubc mbc

Protected
Scenario Set 1
Scenario Set 3

Unprotected
Scenario Set 2


SPM operation
Configuration: MBC installed. UBC and PTX not installed.

gall thomson spm mbc

Protected
Scenario Set 1

Unprotected
Scenario Set 2
Scenario Set 3


PROTECTION STATUS C: Operational Protection. Protected in some foreseen circumstances.


FPSO/FSO Tandem Offloading Operation
Configuration: PTX installed. MBC not installed.

gall thomson fpso ptx

Protected
Scenario Set 2

Unprotected
Scenario Set 1

Not applicable
Scenario Set 3


SPM operation
Configuration: UBC and PTX installed. MBC not installed.

gall thomson spm ubc ptx

Protected
Scenario Set 2
Scenario Set 3

Unprotected
Scenario Set 1


SPM operation
Configuration: UBC installed. MBC and PTX not installed.

gall thomson spm ubc

Protected
Scenario Set 3

Unprotected
Scenario Set 1
Scenario Set 2


PROTECTION STATUS D: Operational Protection. No protection for foreseen circumstances.


STS Crude Oil Operation
Configuration: PTX not installed.

tanker sts

Protected
None identified

Unprotected
Scenario Set 2

Not applicable
Scenario Set 1
Scenario Set 3


FPSO/FSO Tandem Offloading Operation
Configuration: MBC and PTX not installed.

fpso transfer

Protected
None identified

Unprotected
Scenario Set 1
Scenario Set 2

Not applicable
Scenario Set 3


SPM operation
Configuration: UBC, MBC and PTX not installed.

spm tanker transfer

Protected
None identified

Unprotected
Scenario Set 1
Scenario Set 2
Scenario Set 3


Further information regarding protection scenarios and options within specific operational applications is available from the Gall Thomson team.