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Danish Navy’s Knud Rasmussen-class Patrol Ships Are Built for Icy Greenland Waters

It takes a special kind of patrol vessel to protect Denmark’s 200-nautical mile exclusive economic zone (EEZ) around the rugged coast of Greenland – from 58 degrees north to 85 degrees north. The Danish Navy’s ice-capable inspection frigates and offshore patrol vessels (OPV) such as the Knud Rasmussen-class patrol ships, must operate in harsh weather, in bitter cold and ice-choked waters, far from homeport. But working in and around this austere environment is necessary to fulfill Denmark’s sovereignty, fisheries protection, and maritime security missions, not to mention being a vital connection for the small and dispersed communities on Greenland’s coast. The patrols support Greenland’s livelihood – fishing comprises 85 percent of the island’s economy.

Greenland is the world’s largest island, but has a population of just 60,000 – 80 percent of them indigenous Inuit and the rest mostly Danes – living in more than 100 small settlements scattered along the coast. It is also home to Greenland’s huge, ancient ice sheet and glaciers.

Lt. Cmdr. Maria Martens with Sirius Dog

Lt. Cmdr Maria Martens, Royal Danish Navy, and a Sirius dog in Greenland. Martens’ ship, HDMS Knud Rasmussen, visits the Sirius base camps to keep the Sirius teams resupplied. Slædepatruljen Sirius (Sirius Sledge Patrol) is an elite Danish navy unit that conducts long-range reconnaissance patrolling the arctic wilderness of Greenland with sled dogs to maintain Danish sovereignty and police the area of responsibility. The two-man teams patrol for four months, mostly without other human contact.

“Operating in Greenlandic waters differs from other waters mainly because of the ice,” says Lt. Cmdr. Maria Martens of the Royal Danish navy, commanding officer of HDMS Knud Rasmussen (P 570). “And ice is not just ice. There are various types of ice, such as first year ice – salt water in the fjords that freezes up in the winter – or the west ice, coming from northern Canada and the Arctic Ocean. The ice that comes from the northeastern part of Greenland is several years old glacier ice, 3-4 meters thick, extremely compressed and hard and very hazardous to shipping. And then of course there are the icebergs from the big glaciers. These are just some of the obstacles we encounter in the Arctic that you do not have in more southern waters.”

The Knud Rasmussen OPVs have thick hulls, an ice keel and an ‘ice knife’ stem, as well as an ice strengthened rudder. “Our ship can break first-year ice when it’s less than 80 centimeters thick. We can, however, navigate between the ice floes and gently push them away when the concentration allows that,” Martens says.

“The area is often deserted; we may be the only ship within several hundreds of miles, and therefore on our own if we get in trouble,” she says. Martens says that other challenges include the confined and often poorly charted waters in which they navigate. “The areas that are charted are often not very precise, and navigational charts are therefore used with skepticism and caution.”

Last but not least is the weather, which, especially in the winter season, can become harsh and unforgiving. Temperatures can range from 20 degrees C (68 degrees F) in the south to minus 40 C (-40 F) in the north. “Darkness and heavy storms add a certain edge to the patrols,” she says.

Cmdr. Niels Markussen of the Royal Danish Navy, who previously commanded Division 19 in support of Greenlandic and Arctic patrol operations – which is comprised of the new offshore patrol vessels Knud Rasmussen and HDMS Ejnar Mikkelsen (P571), as well as the older cutter HDMS Tulugaq (Y388)agrees.

Knud confined waters

The Arctic OPVs such as Knud Rasmussen, shown here nosing into a narrow inlet, must be able to operate in confined waters.

“The winds and seas are the worst in the world. And most of the waters are uncharted. For most of our patrol area we have no maps,” Markussen says. “We have no idea how deep the water is.”

“We have excellent maneuverability due to powerful engines, a very big rudder and a bow thruster,” Martens says.

The OPVs, while based in Denmark, spend most of their time in Greenland waters, and rotate two crews every two months for each ship.

Markussen says they will occasionally call at some of the remote coastal settlements.  “When we have the possibility to visit settlements we do, in order to show the flag and show the people that we are there for them.”

“Our main tasks are surveillance, search and rescue, controlling the fishing vessels, supporting the local communities (e.g. icebreaking into their small villages, transporting a patient from a small community to the hospital, etc.) and, of course, showing presence,” Martens says.

A very popular task is the summer operation at the northeast coast, where they support the Sirius Dog Sledge Patrol in the National Park, Martens says. “We bring supplies – such as provisions, dog food, and fuel – to their huts along the coastline before their winter patrols.”

Markussen says the crew will be armed when they do go ashore. “There are polar bears, and they are big.”

Knud Rasmussen lowers RHIB

A small-boat crew from the U.S. Coast Guard Cutter Alder approaches the Royal Danish Navy ship HMDS Knud Rasmussen during a personnel transfer and crew exchange, Aug. 16, 2010. One of the ship’s RHIBs is swung outboard from the enclosed boat deck. U.S. Coast Guard photo by Petty Officer 3rd Class George Degener

The Knud Rasmussen has closed decks and a heated work area for the RHIB boats, which are launched to the side, as well as an enclosed hangar in the stern for the Swedish-built Storebro SB90E SAR boat. Each of the OPVs has its own SB90E, which has been adopted by the Danish Navy for use with the Absalon class command ship and the Arctic patrol vessels. Dagmar (SAR 1) belongs to Knud Rasumussen and Naja (SAR 2) belongs to Ejnar Mikkelsen. Markussen says the SAR boat is used in much the same way a helo would be utilized, except in ice.

The SAR boat is launched from the stern, has its own navigational equipment and can achieve speeds of 40 knots. “It is excellent for searching shallow waters and narrow fjords where KNUD cannot navigate, says Martens.

“The inboard RHIB station keeps the RHIB dry, warm and protected when not in use,” says Martens.  “This has a great influence on the engines and the boat in general.  The heated inboard boat decks decrease the risk of over icing and make it more convenient for the crew to work during cold weather.”

There is a flight deck, but no hangar, and the ship does not embark a helicopter, although there is refueling capability.  The Danish Thetis-class fishery protection frigates carry a Lynx helicopter that can operate from the OPVs.

The Scanter surveillance radar, built by the Danish company Terma, has exceptional resolution at short ranges in all weather and visibility conditions. It can be extremely helpful in guiding the helicopter aboard, or navigating along the rugged coast, in the fjords, and in and among the ice.

The ship is armed with a 76 mm Oto Melara gun, along with two heavy machines guns and two light machine guns.  Because the OPVs are built to the Danish STANFLEX modularity concept, they can be equipped with other containerized systems, as well.

Knud Rasmussen patrol

Knud Rasmussen shown on patrol in 2008, in the ship’s normal operating environment, in the ice and far from home. Note the containerized 76 mm gun is not fitted in this photo. Danish Navy photo

“We have a number of container positions where different types of equipment can be stored, such as for hydrographic survey, mine sweeping, or other functions,” Martens says.

Compared to the older, smaller cutters, the crews prefer the new OPVs. There are better accommodations, reduced noise levels, a gym and a sauna. “Most of our crew has served with the old cutters. We have much better work conditions in general – more space, better equipment, more modern,” she says. “The crew is only 19 (compared to 13 on the cutters) but we can accommodate 43 people.”

The Knud Rasmussen OPVs have more stamina in bad weather, and, she says, endurance is increased remarkably, up to 25 days, compared with 8-10 days for the old cutters.

“When not being on a particular task we spend our time training,” says Martens. “We do internal training such as damage control and man overboard drills.  The navigators and helmsmen practice our ship handling and maneuvers by challenging ourselves navigating within the very confined waters. In that way we maintain our appreciation for the navigational challenges and techniques.”

Markussen says the patrols are never boring. “Nature always plays with you. You have amazing geography; including mountains, glaciers, and rivers, and fantastic light – in the arctic night you have northern lights as green ghosts in the sky. In the summer its daylight 24 hours a day, and in the darkest winter its dark 24 hours a day.”

Martens speaks highly of her crew. “Their level of expertise and professionalism is very high and their commitment is incredible. They enjoy a great amount of freedom and are very self-driven and responsible. Besides the daily work and the social aspect we are privileged with the most outstanding scenery and unique experiences like polar bears, the aurora borealis and whales.”


Capt. Edward H. Lundquist, U.S. Navy (Ret.) is a senior-level communications professional with more than...

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    Morten Sorensen

    Great story. I have had seven tours with the Danish Navy in these water. Fantastic