Oblique icebreaker gives better access to Arctic waters
- 13 September 2013
- From the section Technology
Icebreakers trawl the world's frozen seas, cutting a path for other ships in the harsh Arctic winter. Now, a new kind of ship that can drift sideways could make traffic - and trade - easier. Could the maritime technology change life in the extreme north?
Traditional icebreakers use their weight, size and power to bulldoze crusts of ice as much as 3m (10ft) thick when the sea freezes over.
In its wake, this special class of ship leaves a narrow, open lane along which other vessels can follow.
In recent years Arctic ship traffic has been rising dramatically, while cargo and crude oil carriers have become bigger and bigger.
Often, two icebreakers as well as supporting vessels are required to open a route wide enough for these ships to pass through.
But a new kind of icebreaker under construction in Helsinki, Finland, has the potential to change the way shipping operates in the frozen north.
The Oblique Icebreaker NB 508, made by the Arctic ship builder Arctech, will become the first of its kind to travel sideways through the ice rather than pound it head-on, cutting a channel as much as 30% wider than conventional icebreakers can manage.
The 76m euro (£65m) ship has been designed with an asymmetrical hull that inclines steeply and is heavily reinforced on its left side, to bear the brunt of the icebreaking.
Although the ship can go faster in open water or while icebreaking head-on, when moving sideways it will creep forward at a speed of just 2 knots (2.3mph), and can only tackle thinner ice of up to 0.6m (23.6in) depth.
But experts say the ship's ability to cut a path of 164ft (50m) outweighs those factors.
Prof Klaus Dodds of Royal Holloway University of London says: "Any talk about wider pathways is of huge interest to the Russian Ministry of Transport," for whom the NB 508 is being built.
Maritime traffic is taking off in Russia's strategic Northern Sea Route. Forty-three vessels sailed that route in 2012, up from just three or four in 2010.
Analysts expect commercial activity to grow further, as melting polar ice makes the sea navigable for more of the year.
Russia charges transit fees to ships moving in its Arctic waters and requires that every ship is accompanied by one of its icebreakers.
But the icebreakers in its fleet are becoming old and many are too small for larger ships and tankers.
The new icebreaker technology is likely to be marketed to energy companies as a boost for shipping and drilling, since most of the ships using that route carry liquefied natural gas (LNG) or crude oil to East Asian markets.
But Prof Dodds says: "The big uncertainty with the Northern Sea Route - as with anywhere in the Arctic - is weather conditions and sea ice conditions, which can change quickly.
"The thing that is of huge concern with the Northern Sea Route - and this of course affects insurance premiums - is the capacity of search and rescue. How do you deal with an emergency?" he adds.
In the Arctic, the sparse population living in tiny communities across huge distances means it can be hard to relieve a ship in distress. In addition, there are fears over how to cope with an environmental disaster.
The NB 508 is being built as an emergency and rescue vessel that can also clean up oil spills.
At the heart of the boat's design are three rotating "azimuth" propulsors that can turn 360 degrees placed asymmetrically along the ship's keel, with two propulsion units at the back and one at the front to give the icebreaker a high degree of manoeuvrability.
"Collecting oil is basically done by the right-hand side of the ship," says Mika Willberg, project manager for Arctech. "There is an open hatch and you guide the water - the oily water - inside to an integrated skimmer system."
The right side of the 76m-long vessel, with a deadweight of 1,150 tonnes, will move like an arm to sweep up the oily water, Mr Willberg says.
Once inside the tank, the water and oil will be separated by brushes fitted to the inside, and the ship is able to work on cleaning up oily water even in harsh weather conditions.
"The vessel going sideways to collect oil is a new function," he adds.
Craig Eason, technical editor of shipping industry journal Lloyds List, who spent 10 days on board an ice class tanker, says: "Navigating through ice is particularly intense.
"What the crew are doing is to look intensely at the ice, trying to find a passage through it to see which way is the best way to go," he adds.
"See which way it's drifting, see whether there might be a fault in the ice that they could push the vessel through, looking at the ice maps, looking at the ice radar and just doing this intense assessment."
The NB 508 will also have two control centres - for operating in conventional and oblique mode. The NB 508 can also undertake firefighting, towing and rescue operations.
The Arctech project manager says the concept for the oblique icebreakers was born 15 years ago when the ship builder, formerly called Aker Arctic, held an internal competition for a new idea. The winning concept was an "oblique mode", which turned into a patent in 1997.
"They saw possibility in that," Mr Willberg says. "The company made some tests with normal icebreakers, eventually developing the whole form of the vessel."
Different versions of the vessel were put together over the years, but Mr Willberg says the design never sold, perhaps "some of the customers were a little suspicious" of whether it could actually be pulled off.
But even though the NB 508 is due to be delivered to the Russians in early 2014, there are obstacles to reproducing the design for wider use.
From its home port of St Petersburg, the NB 508 is designed to operate in the icy waters of the Baltic Sea's Gulf of Finland.
"With that in mind it will have a certain limit on its fuel capacity, so taking it further afield could be problematic in terms of its range," says Mr Eason.
"But there is a need for more infrastructure in the Arctic, that's for sure."