Gathering a larger audience than in several years, the conference Norsk Offshoredag was arranged yesterday, Wednesday 27th May. This year Inocean was represented with two speakers, Mr John Riis and Mr Kjell Faafeng.
John Riis presented a quiet spectacular Inocean-project, where six Suezmax tankers were converted to heavylift vessels for Frontline Management.
Fast track construction of heavylift vessel
Riis guided the audience through every step of the project, showing them the challenges met in the process where the concept was to remove the old cargo part of a Suezmax tanker, design and build a new midship section, and then connect old and new modules. The result: A heavy lift vessel designed to transport JackUp rigs up to 20 000 tons.
Inocean was overall naval architect in this project with a scope including all structural and system design for classification documentation. One of the biggest challenges was the execution time, said Riis. Total construction time, including project engineering, from start to delivery of the first vessel was only 18 months. The project achieved class approval of main steel in just two months.
Other challenges that John Riis commented in his presentation:
- Structural integrity of aftship
- Damage stability
- 100% Tank filling
- Yard follow up
- Electrical engineering
First FPSO in US Gulf of Mexico
BW Pioneer will be the first FPSO in the US Gulf of Mexico, starting operation in January 2010. Inocean is BWO's engineering partner with a scope covering hull and topside structural engineering, technical documentation and drawings for class approval during the conversion from tanker to FPSO.
Kjell Faafeng presented the ship's main particulars and made a point out of the challenges following the fact that the vessel will operate at the Cascade Chinook field, which API has categorized as high risk hurricane area. Another challenge: In this project the Inocean team, in addition to DNV, also had to fulfill the rules and regulations of API, Marpol and the demanding General Technical Descriptions/Requirements coming from Petrobras America Inc GTD.
Faafeng also pointed out several challenges in the fields of ULS (Ultimate Limit State for Hull and Deck Modules & Equipment), FLS (Fatigue Limit State for Hull), ALS (Accidental Limit State for Hull and Marpol Damage Hull.
He ended his presentation with this conclusions:
- Conversion projects differ from newbuilding since structure already has demonstrated its actual fatigue performance (trading as tanker)
- Identification of critical details - with high confidence level
- Required design fatigue life as FPSO is 16 years included DFF of minimum 2 on all details
- Details of stiffeners connection to bhd was improved in waterline area
- Relatively long design life as FPSO, with limited possibilities of repair, necessitate thorough fatigue analysis
Complete presentations:
Tanker to heavylift vessel, click here
BW Pioneer, click here