Proceedings Publication Date
Presenter
Tjomme van Norden
Presenter
Author
Tjomme van Norden
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Abstract
June 2005 Allseas announced that it would build a new 225 m long dynamically positioned pipelay vessel, to be named Audacia. The execution of Audacia’s first pipelay project started in December 2007.

The concept of Audacia has been developed entirely in-house by Allseas. Being the third DP pipelay vessel, the 20 years experience has been included in her design. Most notably is the stinger on the bow of the vessel, which results in sailing backwards while laying pipe, but leaves the original propulsion in tact. Besides the original propulsion for transists, six 5 MW thrusters keep Audacia in place during operation and allow installation of pipelines in ultra deep water.

The pipelay systems are designed for upto 60 inch diameter pipelines with maximum tensions of 525 ton in 3000m of water depth. The three 175t tensioners hold the pipe during installation and the two 275 t A&R winches can lay the pipe on the seabed. The in-house developed welding system “Phoenix” let Audacia lay upto 10 km of pipeline in one day. The firing line, the welding area onboard the vessel, also incorporates a dual piggy back firing line so that two additional small pipelines can be constructed and installed in parallel by strapping them to the ‘main line’ prior to over boarding. For the installation of large structures a 550 t A-frame is installed on the side of the vessel.

The integrated project team of Dutch shipyard Keppel Verolme and Allseas has resulted in the successful conversion of the bulk carrier “Geeview” into pipelay vessel Audacia. Combining the ship-building experience of Keppel Verolme and the pipelay experience of Allseas enabled that this technically challenging project could be completed in a demanding time schedule.

Now Audacia is operational and has successfully used her systems, Allseas is preparing for the next challenge: the 48,000 t heavy lift vessel Pieter Schelte.