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A study in flexibility: The refit of Allseas Solitaire

-- FROM THE FULL PICTURE MAGAZINE --

As Solitaire, the world's biggest pipelay vessel, rushes from job to job, the ship's technical team must squeeze vital refits into the slimmest of openings. A recent upgrade of Solitaire's Kongsberg DP and automated vessel management system tested the flexibility of supplier and customer.

Allseas solitaire pipe-laying vessel
Solitaire, the world's biggest pipelay vessel, recently upgraded DP and automated vessel management systems.

In February 2009, Allseas' Solitaire steamed to the port of Rotterdam for an express refitting of its DP and automation systems. The timing of this job had changed numerous times in the preceding months, most recently in January.

"Originally, the refit was planned for 2008. That didn't work out, so we had moved the job to late 2009. Then we found a window in March-April 2009," said Solitaire's technical superintendent, Willem Pesman of Allseas.

With one question of timing (when?) answered, Pesman pushed Kongsberg on the second (how long?). "We presented Allseas with a project schedule, and they responded 'can you do it in half the time with twice as many people?'," said Vegard Ryen Skullerud of Kongsberg.

In the end, Kongsberg completed the project in roughly seven weeks, according to the tight schedule, and Pesman lauded the professionalism, flexibility and speed of Skullerud and the Kongsberg team. "They showed a great ability to respond to changes, and – once the timing was settled – we all moved very quickly," he said.

Preparatory work, including cable-pulling, took place off of Egypt while the ship was in operation. Work in the yard took place over seven weeks. As many as two dozen people on Kongsberg's team lived and worked from the ship. Skullerud, who spent 53 nights on the ship in Rotterdam, gives much credit to Solitaire's crew. "The relationship with the crew was like nothing I'd experienced before," he said. "We worked very closely as a team. This crew puts its honour into the ship; it's their home."

Faster, larger, deeper

Allseas' relationship with Kongsberg has always been tight. Shortly after Allseas was founded in 1985, it began exploring designs for a DP-controlled pipelay vessel. A novelty at the time, the logic behind it was simple; in competition with anchored pipelay barges and platforms, a DP pipelayer could work much faster and more efficiently.

Seeking DP expertise, Allseas turned to Kongsberg, which supplied the world's first DP pipelay vessel, Lorelay. Since then, Allseas has returned to Kongsberg for each of its subsequent pipe-layers, including Solitaire, which was completed in the mid-1990s. This ship has set countless records both for speed and depth of pipelaying (most recently, at 2775 metres).

Eager to increase the ship's capabilities, Allseas doubled Solitaire's tensioner capacity in 2005. This, in addition to an elongated stinger, allows Solitaire to lay heavier pipes in deeper waters. To counter the added weight, extra buoyancy was added to the ship's aft. The added length and weight adversely impacted workability, however, as the ship's rearmost thrusters (7 & 8) struggled to maintain Solitaire's position in extreme currents.

The answer was two additional thrusters in the ship's aft. In 2007, Allseas began preparations to install the two new thrusters, and it became immediately clear that the DP system would need modification. "The DP system from the mid-1990s was incapable of handling so many thrusters. The conclusion was that the DP and automation systems would need upgrading," said Skullerud.

Allseas decided to fit Solitaire with the K-Chief 700 automation system, K-POS 22 and 12 (class 3) and K-Thrust. The contract was signed in April 2007, engineering and production lasted until the factory acceptance test in August 2008 and installation was done in phases from late 2008 to summer 2009.

Sharing a ship and a vision

Sometimes for the sake of expediency, sometimes out of necessity, the teams responsible for the refit lived onboard Solitaire, which can house a total of 420 people. In November 2008, a Kongsberg sub-contractor (Servie) pulled up to 20 kilometres of cable while the ship was operating off of Egypt. This required some additional safety and security measures, but the time saved was invaluable.

Upon Solitaire's arrival at the Rotterdam shipyard, Kongsberg's team of between 19 and 23 technicians and engineers moved onboard. These teams slowly moved the ship's operations from the older systems to the newly installed systems, all without using shore power and with 300 personnel living aboard the ship.

The presence of the ship's crew during the commissioning work was both intentional and beneficial. "We have a tremendous amount of knowledge onboard the vessel itself in its crew. There are only three of us in the technical department, who work with this vessel from shore," said Pesman. "Most of the expertise is on the ship itself.

"We wanted the crew to be onboard during the installation and commissioning process because it would give them a unique opportunity to learn the systems and gain knowledge."

Skullerud also admired the crew's attitude and knowledge: "The documentation on this ship is truly flawless. The engineers and electricians know every cable on the ship, every termination. Usually during a job like this, we do a number of spot-checks of the I/Os, as insurance. Often, we have to ask crews to do this, and they comply grudgingly. In this case, though, the crew was pushing us to double-check everything. You can sense the pride they have in this ship."

Pesman concurred: "It's the biggest vessel in our fleet, which means there's some prestige in it. It's also a result of the management."

Always ambitious

After approximately 7,000 hours of work onboard, Kongsberg's teams wrapped up their work on 22 April with the completion of the customer acceptance tests. Although some minor issues remain to be settled (including an adjustment after the two thrusters are installed later this year), the Solitaire refit can be classified as a success.

"I believe we've gotten value for money, and I appreciate the professionalism we saw from Kongsberg in completion of the project," said Pesman. "Feedback from the crew regarding the new systems has been positive. The bridge teams are particularly excited about the functionality that they have discovered in the newer ship control systems."

The new thrusters will be added later this year. Once they're in place, the vessel will have improved workability, with thrust in a more effective location.

This will hardly be the final ambitious project for a company that has made a living of doing what none have done before. Innovation and new technology is central to Allseas' philosophy. For a technical superintendent like Pesman, who must keep all the new technology maintained and spare parts in stock, it is surely priceless to have a flexible partner who delivers on its promises.

Making DP pipe-laying operations possible

The S-Lay style pipelay systems (assembling the pipeline horizontally before lowering it down to the sea bed) favoured by Allseas enable its ships to install larger pipe, deeper than conventional J-Lay competitors. Holding the pipeline on Solitaire are three tensioners, which control the powerful forces on the pipe itself. The DP system onboard combines the thrust available with the force created by the pull of the pipeline to keep the vessel in position, and move forward. Accurate positioning is critical, as too little forward thrust would lead the pipeline to buckle near the seabed and too much forward thrust burns too much fuel and strains the tensioners. A tension control master system monitors the tensioners and provides a single input to the DP system, which responds with the necessary thrust.

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