The Vanguard of ocean transport

Heavy transport firm Dockwise performed a market first with the transport of a ship-shaped FPSO, the Armada Intrepid. Elaine Maslin explains.

Images from Dockwise.

When the Dockwise Vanguard was conceived, Dockwise, part of the Boskalis Group, had a vision for a new market – transporting the world’s largest cargos, including floating production, storage and offloading (FPSO) vessels.

It hasn’t taken the vessel – the largest of its kind – long to prove its worth, as well as the feasibility of such a feat.

The vessel recently delivered its first ship-shaped FPSO cargo, Bumi Armada’s Armada Intrepid, which also happens to be one of the three largest cargos ever transported. It’s worth noting, before delivering the ship-shaped Armada Intrepid, the Dockwise Vanguard had only just completed the transport of the cylindrical, Sevan-design, Goliat FPSO from Hyundai Heavy Industry’s yard in South Korea to Hammerfest, Norway, for Eni Norge - then Vanguard’s largest cargo.

What’s more, the 110,000-tonne capacity Dockwise Vanguard’s next major job will be yet again bigger in size and weight – Total’s 85,000-tonne, 250m-long, 60m-wide Moho Nord floating production unit (FPU), which will be transported from Hyundai Heavy Industry’s yard in Bulsan, South Korea, to West Africa early 2016.

All three projects are feathers in Dockwise’s cap. However, transporting the FPSO is the biggest and serves to prove the ship-shaped FPSO transport concept. Being able to transport FPSOs using a heavy transport vessel offers FPSO operators and owners a faster and safer alternative to the current industry norm – slower wet tows using tugs.

“This is opening a new market,” says Taco Terpstra, senior project manager for the Armada Intrepid project, Dockwise. “We just completed transporting the heaviest cargo (the 107m-diameter, 64,000-tonne Goliat), and now the Armada Intrepid, our first ship-shaped cargo. Next, we will be getting ready for Moho Nord. To have these three contracts in a row shows why we brought the Dockwise Vanguard to the market.”

Step by step, the 60,000-tonne Armada Intrepid is loaded onto the Dockwise Vanguard.

Safe loading

The Armada Intrepid, previously known as the Schiehallion FPSO while it was working for BP, west of the Shetland Islands, was safely and successfully loaded on to the Dockwise Vanguard in Rotterdam’s Caland Canal on 8 May, just eight days after the heavy transport vessel’s arrival in port.

The job, loading and transporting the Armada Intrepid, posed the Dockwise project team some interesting and unique challenges, due to the dimensions of the cargo. Terpstra says: “The configuration of the loading marks this out from other projects. At first sight, it looks like a normal transport, but what’s quite novel is that it was the first ship-shaped FPSO we transported on the Dockwise Vanguard. Weighing 60,000-tonne (42,000-tonne plus ballast), it is among the top three heaviest cargos ever transported. That, in combination with its ship-shape, with a 245m-long, 45m-beam hull, makes the this project quite interesting.”

Unlike normal loads, which are positioned on the Dockwise Vanguard’s 275m x 70m deck by ballasting the vessel beneath the water line and floating the load across its beam, the Armada Intrepid, which is too long to float across the beam, had to be floated over the deck via the Dockwise Vanguard’s stern, carefully slotting between the two aft casings, or stability boxes, with just 2.5-3m leeway either side.

This loading configuration meant more handling (tugger and tow lines) was required compared to normal jobs, due to the careful maneuvering required. Getting the water depth and tidal window right was key, making loading location and timing crucial.

Preparation was also key. The Dockwise Vanguard first had to be cleaned, following its transport of the Goliat FPSO. Then, the vessel had to be fitted with cribbing material – a 600mm-high wooden layer fixed with angle bars bolted to the deck, on which the Armada Intrepid or any other load would rest. In addition, the guide posts, against which the FPSO is positioned, had to be installed. All of this was done before 8 May.

To make sure the FPSO remained secure during the transit, about 54 sea fastenings were fitted once the vessel was loaded.

During the voyage, the FPSO, sea fastenings and cribbing were regularly inspected and, for this transport, Dockwise tried something new – permanent, real-time pressure monitoring on the cribbing.

All in all, it’s a big job. For Leerdam, the biggest achievement is proving the FPSO transport concept.

“For me, this is an innovation, a first,” he says. “We are able to show to the market this is a better, faster, more efficient solution to transport ship-shaped FPSOs from one side of the world to another, be it for refitting or new builds. The alternative is a wet tow – at half the speed. We expect the Dockwise Vanguard to cruise up to 12 knots. Wet tow speed is about 6-8 knots. You can also be more flexible, going around bad weather. You are safer and more in control.”

In fact, insurance premiums for wet tows are 10 times more expensive than the dry tow alternative, showing that insurance companies recognize that dry transport is a safer solution, says Hans Leerdam, category manager, strategic vessels, Boskalis Offshore.

The Dockwise Vanguard, with the Armada Intrepid on board, arrived in Batam, Indonesia, 8 July, having sailed via the Cape of Good Hope, without the need for tugs and in less time than a wet tow would have taken.

Now Dockwise is preparing the Dockwise Vanguard to transport the Moho Nord, in 1Q 2016, with possibly another job in-between.

To accommodate the Moho Nord, a vessel wider than the Intrepid, Dockwise had been considering removing one of the aft casings, for the loading, and then reinstalling them. The firm is now planning a permanent solution, which will mean moving the vessel’s aft casings further apart, on permanent out riggings, to make the slot big enough for the Moho Nord, and other similar wide-beam units, to float in across the stern, like the Intrepid, Leerdam says.