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Semi-Submersible Drilling Rig move

For the third time since 2008, ALS were given the opportunity to arrange the deep-sea wet-towage of the Croatian owned Semi-Submersible Drilling Rig (SSDR) named "ZAGREB-I".

14th December 2010

The Croatian rig owner was delighted with the previous 2 performances (Abidjan to Pascagoula + Pascagoula to Mexico) and therefore decided, for a third time, to award this movement again via the services of the Moerdijk based ALS Project division.

Following a 1.5-year period of drilling works in the Mexican Gulf, on account of a US oil company, the Croatian Oil Services Company (CROSCO) signed a new contract for Drilling works in Libya, set to commence around March 2011.

For this purpose, ALS have been involved in undertaking the job of towing the platform from its offshore anchor site in the Mexican Gulf (Ciudad del Carmen) to its next anchor site in Malta, where she is presently making some routine maintenance work as well as some smaller repairs, before final towing to Libya.

The rig, with its considerable measurements of 103.4m x 106.3m and a total height of 110.6 m was ballasted up to a safe tow-draft with all 5 legs in upper position achieving the best possible tow conditions, with lesser adverse behaviour during the tow.

Due to the shape of the oil rig (Pentagon type, 5 legs) and the difficulty of towing these types of platforms, two of worlds' larger Anchor-handling seagoing tugs (AHT) were chartered. Using these particular types of tugs allowed not only the tow of the rig across the Atlantic and into the Mediterranean Sea but also the heaving of 12 anchors and anchor re-positioning in Malta.

The total pulling power produced by both tugboats was over 400 tons Bollard Pull (BP), totalling 12,000 Horse Power (BHP). The convoy departed early in September and with a going speed of between 4.5 and 6 knots arrived in Malta less than 60 days later.

For all parties involved, the difficult shape of the rig, as well as the timing period (hurricane season and oil spill in the US Gulf), the routing cross-Atlantic and passing Strait of Gibraltar, were the major factors for this project.

For the third time, and with no delay or any problems on the way, the platform was delivered at exactly the right time and position.

For further information please contact:

Jill Peacock – Group Marketing Manager

Tel: +44 (0) 1482 796214