Arctic Princess

The Leif Höegh-managed Arctic Princess is ‘winterised' and ready for a long and full service life trading in the North Atlantic

Delivered by Mitsubishi Heavy Industries (MHI) earlier this year to Leif Höegh & Co and Mitsui OSK Lines (MOL), the 147,200m³ Arctic Princess is, for a short while at least, the largest LNG carrier in the world. It is also the first of a fleet of ships to be chartered by Statoil for the carriage of LNG from Norway’s Snohvit project.

The other three vessels that have been chartered to Statoil for Snohvit cargoes are a second Höegh/MOL ship from MHI, Arctic Lady, to be delivered in April 2006, and a pair of 140,000m³ ships, also with spherical tank containment systems, to be operated by K Line Europe. The first of the latter pair, Arctic Discoverer, has just been delivered by Mitsui Engineering and Shipbuilding. The second K Line ship will be delivered by Kawasaki Shipbuilding Corporation in June 2006.

Because Snohvit will not come onstream until December 2007, Arctic Princess has been sublet to the BG Group on a short-term basis.

When it commences operation, Snohvit’s terminal on Melkoya Island near Hammerfest will not only be Europe’s first LNG export project but also the world’s northernmost facility for handling LNG. The Snøhvit project will produce LNG, at a rate of approximately 4.2 million tonnes per annum (mta), using gas from fields located in the Barents Sea. Buyers for this gas have already been lined up in Europe and the US.

The robust design of Arctic Princess will enable the ship to operate over a long service life in the extremely harsh environments that can often be encountered in the North Atlantic, especially in the wintertime. The hull design, which is based on a North Atlantic trading life expectancy of 40 years, has benefited from a substantial hull girder analysis carried out by Det Norske Veritas, the ship’s classification society.

Although Arctic Princess and the other ships loading at Melkoya will not encounter any permanent ice cover, they will be subject to such rigours as extreme cold, icing from sea spray and snow, occasional ice floes and fierce North Atlantic storms.

These conditions have been catered for through the incorporation of various ‘winterisation’ design features on board Arctic Princess. The ship has a fully enclosed bridge, including bridge wings, a heated booth for the watchman at the manifold and an extra drying room at deck level for stowing winter outfit. The heating/cooling capacity of the accommodation block has been increased, as has the insulation of the bulkheads. In addition, deck access, or weather, doors at the side of the accommodation block have been recessed 1 metre and the doorframes have electric/steam trace heating.

Heating has also been provided for other parts of the ship. For example, the underdeck passages are heated by steam radiators while the flying passages, or catwalks, are equipped with steam de-icing pipes under the grating. The mooring work stations forward and aft are warmed by means of underdeck heating in the boson store and the steering gear compartment.

The port and starboard manifold platforms are both equipped with steam radiators while the top walkways and access ladders in way of the cargo compressor room are also heated. Similarly, the abandon-ship mustering area, including the walkway to the freefall lifeboat, is equipped with de-icing steam pipes. Leif Höegh decided to upgrade the propulsion system for the man overboard boat from an outboard engine to a diesel inboard engine because of the improved ease of heating the latter.

To ensure good visibility selected windows on the bridge are heated using warm air blowers, while the front windows in cargo control room and in the master’s office are also heated. Furthermore, the wipers themselves for the bridge windows are heated as are those for the rotating ‘free-view’ windows. A three-way valve, located inside the bridge, is used to control the flow of fresh water to the bridge wipers.

Circulating pumps are used to help prevent the contents of fresh water and distilled water tanks from icing up. Seawater, fresh water, compressed air and oil system pipework is arranged in protected spaces below deck wherever possible. Exposed fresh water and sprinkler pipes have drain plugs situated at their lowest points so that they can be drained when not in use. All hydraulic oil is of the low-temperature grade, as is the lubricating oil used in deck equipment.

Other winterisation features include electric heaters for the de-icing of radar antennas and other equipment on top of the wheelhouse; hot water for anchors, cargo manifolds and tank domes; steam pipes for deck machinery; portable steam hose connections at suitable locations; and an additional horizontal bar on the bow railing to enhance safety levels, not least when the deck is slippery.

Leif Höegh has a long pedigree in LNG shipping, the company having built the first spherical tank LNGC in 1973. Arctic Princess is the fifth ship in the current Höegh fleet and the company has ambitions to expand this fleet as it participates in many of the tenders currently going out for the ships that will be needed to serve new LNG projects.

Leif Höegh has developed an LNG Shuttle & Regasification Vessel (SRVTM) concept and the company has recently filed, jointly with Suez Energy, an application with the US Coast Guard for the construction of a deepwater port terminal in Massachusetts Bay that would receive such vessels. This proposed project, named Neptune LNG, calls for the use of three Höegh LNG SRVs to serve the terminal in a rotation schedule that ensures that there is always one ship moored at one of the two offloading buoys regasifying and discharging cargo into the New England gas grid via a subsea pipeline. Other such projects are also currently under investigation. LNG