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PTIL/PSA

IN SERVICE EXPERIENCES WITH SHIP-SHAPED

FLOATING PRODUCTION UNITS

Marita Halsne, Narve Oma, Gerhard Ersdal, Arne

Kvitrud, Roger L. Leonhardsen, Morten Langøy, Terje

Andersen, Lars G. Bjørheim

OMAE2020-19287

PTIL/PSA

A report on the Norwegian FPSO and FSO fleet

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Total number of FPSOs and FSOs on NCS: 17

Current number for FPSOs and FSOs on NCS: 13

Pictures from: Oma, N. Presentation at PSA’s seminar 2006

PTIL/PSA

Differences between FPSOs, FSOs and tankers

Pictures from Teekay

PTIL/PSA

Reported incidents from 2000 - 2019

Incidents Number of incidents sinceyear 2000

Cracks 494

Green sea 4

Stability 3

Mooring line failure 6

PTIL/PSA

Crack prone areas on FPSOs and FSOs

Structural connections important for the integrity of global and local strength:

• Moonpool area in main deck and bottom.

• Inner- and outer knuckellines.

• Bracket termination of midship section.

• Termination of stringers and longitudinals.

• Termination of cross-ties.

• Cut outs with penetrations in main deck.

• Top side support towards main deck (stools).

• Disconuity of bilge keel, main deck and bottom plate.

• Block joints

DNVGL og TSCF

PTIL/PSA

Cracks in FPSOs and FSOs.

WBT Cargo WBT/Cargo Void Bow Deck

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Insignificant Minor Major

CRACKS ON ALL 17 PRODUCTION UNITS

GIVEN BY LOCATIONS OF THE CRACKS.

THE CRACK AS CLASSIFIED INTO CLASSES OF SEVERITY

PER ANNUM ON ALL 17 PRODUCTION UNITS ON THE NCS

IN THE PERIOD 2000-2019.

PTIL/PSA

Definition of cracks of major severity

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Pictures from: Oma, N. Presentation at PSA’s seminar 2006

PTIL/PSA

Definition of cracks of minor severity

Pictures from: Oma, N. Presentation at PSA’s seminar 2006

PTIL/PSA

Definition of cracks of insignificant severity

Pictures from: PSA database

PTIL/PSA

Green sea incidents

Photo: Per Meidel fra boken “Belastninger på skip” av Carl A Carlsen

PTIL/PSA

Mooring and heading control

PTIL/PSA

Stability incidents

Photo: Associated Press

PTIL/PSA

Conclusion

Crack in bilge keel Crack in deck longitudinal

Pictures from: Oma, N. Presentation at PSA’s seminar 2006