One minute – that’s all the time it took for CPP jacket to be launched from the launch barge to the final upright position. In few minutes a structure which required months to design and build can be lost or damaged during this sensitive operation. The Central Processing Platform (CPP) is located in the Su Tu Vang field in Block 15-1 offshore of the Socialist Republic of Vietnam. The CPP jacket, being a vertical launch differs from the conventional horizontal launch jacket.

The critical aspects of a vertical launch are:

• High launch velocity.
• Large stern submergence for launch barge (CBL-102) as it is required to support jacket for longer time to provide the required buoyancy.

Due to high velocity of launch operation, clearance between seabed and jacket will be less compared with typical conventional launch operation. This was further aggravated by the limitation of water depth at launch site.

It is therefore evident that the vertical launch operation is quite critical in terms of buoyancy, clearances and barge loading. Hence, this calls for highly specialized and detailed engineering to simulate the actual behavior of the jacket during the launch. The engineering for this critical operation was performed by the naval architecture group of Construction Support Engineering, Dubai. Special consideration was incorporated in the analysis to simulate the actual behavior of the jacket like refining the drag/damping coefficient of the barge, sensitivity study of weight/COG movement.

As shown in figures below, the close co-relation between the predicted and the actual behavior of the jacket during the launch operation confirms the analysis methodology and justifies the detailed engineering efforts by the CSE naval group.

FACTS OF CPP JACKET

CPP jacket is the first jacket designated for vertical launch operation. The following information lists the main particulars of the jacket:

Number of legs Overall Height Mudline Horizontal to Top Horizontal Top Horizontal above MWL Jacket Length Jacket Breadth Jacket Weight including Rigging Jacket Buoyancy Minimum required water depth for launch

: 8 : 60.10 m : 53.10 m : 7.00 m : 58.0 m : 48.0 m : 3991 MT : 5290 MT : 57.0 m

BARGE VIEW

SIDE VIEW

Prepared by: Mohamed Taha