“We’ve seen the oil and gas industry extending its reach steadily north in recent years,” says Ove Wilhelmsen of Wärtsilä, drawing with it a gradual change in support craft design.
As always it’s a balance between costs, flexibility and
especially, in the case of icy waters, the elements. So, the new VS 485 PSV Mk III Arctic is pulling together a number
of tricky parameters including meeting DNV’s ice class ICE 1B to give a vessel
which, with icebreaker assistance, can operate in the cold winters of the arctic region.
Ove Wilhelmsen explains that Wärtsilä’s VS 485 has been involved in a gradual evolution for over a decade: “Though it’s an established name these ships actually have very modern hull lines as they’ve consistently been optimised for the tasks in hand.” Alongside this have been onboard power and distribution developments including the Low Loss Concept; this ties together four switchboards to give high levels of redundancy and significant fuel savings and reduced emissions.
However, he points out that with class rules, regulations, equipment and other parameters all pulling at the design you have to be really clear about exactly what the vessel’s sphere of operations is going to be. “You can always ask for more of one thing or another”, but he adds this can compromise the design: “Really these VS 485s are the trucks of the sea,” he says, pointing out that it takes “common effort” with an experienced builder – such as longtime associate Kleven Shipyard - to keep the weight down. It’s an especially relevant skill since raising the game to meet ICE 1B classification means additional strengthening around the hull while still keeping it inside the 5,000 dwt envelope.
Alongside this there is DNV’s ‘Winterisation Basic’ upgrade. “Winterisation means bringing more areas under cover; this protects the equipment but it also makes working outside safer, plus there are elements like the heating of gangways and handrails, either by using electrical coils or even by running warm water through them,” explains Mr Wilhelmsen.
But colder waters and risk of ice contact means more meaty propellers. This, says Mr Wilhelmsen, presents the operators with a challenge: “Bigger propellers need to have more power to get the same speed and acceleration.”
“Some owners say that in colder waters top speed is not that important, but that right now in warmer waters, both the lower fuel consumption and higher speed are necessary. So, a good compromise is to build the vessel for Ice class 1B, then equip it for 1C. When it needs to operate in northerly waters, you can change over the propeller blades fairly easily. Just like putting on winter clothes.”
This approach of keeping an eye on the future is showing in other ways too. “We are seeing support ship owners look far more at the long term perspective than they used to,” says Mr Wilhelmsen. “Many actually now ask for medium speed engines: while high speed engines have a lower initial investment, being a little cheaper to install, you have to accept the ongoing costs of more maintenance.”
So, he concludes: “We are really very pleased that our latest designs have been accepted by REM Offshore with the nine cylinder Wärtsilä 20 inline engines because it means lower lifecycle costs, and overall this results in a better ongoing relationship with the owners.”
By Stevie Knight
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