Thetis / Stanflex 3000 - Inspektionsskibet
Danish Thetis class multi-role frigate used for fishery protection, surveillance, air-sea rescue, anti-pollution and ice reconnaissance. The Royal Danish Navy had a varying number of ships of different classes located in the Arctic at different times of the year, including une or two ocean patrol ships of the Thetis class.
The Thetis class ocean patrol ship is a large patrol ship of the size of 112 m (length) x 14 m (beam) x 6 m (draft). The max. speed is 20 kn and the range 9000 nm. The staff size can be between 51 and 91. It has also space for sheltering 200 people for a shorter time. It has ice-reinforced hull for navigating in icy water and ice-breaking capacity. All in all, the navy had four ships of this class.
Thetis was a goddess of the sea and the leader of the fifty Nereides. Like many other sea gods she possessed the gift of prophesy and power to change her shape at will. Because of a prophesy that she was destined to bear a son greater than his father, Zeus had her marry a mortal man. She bore a son, the celebrated hero Akhilleus (Achilles). In her desperate attempts to protect her son during the Trojan War, Thetis called in many favours from the gods. These included Hephaistos (Hephaestus) and Dionysos, both of whom she had given refuge in the sea as they faced crises of youth, and Zeus, whose throne she had protected by summoning the giant Briareus-Aigaion (Aegaeon) when the gods had sought to bind him. Thetis's name is connected with the ancient Greek words thesis "creation" and têthê "nurse".
The armament consists of one Otobreda 76 mm Super Rapid main gun, one or two 20 mm guns from Oerlikon, and depth charge throwers. The Super Rapid gun has a rate of fire of 120 rounds per minute and a range of 16 km. The fire control system is the CelsiusTech 9LV 200 Mk 3. A FLIR Systems Inc AN/AAQ-22 SAFIRE thermal imaging system is used for surveillance. All weapon and equipment systems are connected through the frigates' command, control and communications system.
The frigate has a landing deck with a landing spot for a single helicopter. Helicopter support arrangements include a glide path indicator (GPI) and a flight refuelling system. The hangar is equipped for helicopter maintenance and has capacity to hold a Lynx helicopter without having to fold the helicopter tail. The hangar is fitted with a full width door.
The frigate has a double-skinned hull up to two metres above the water-line. The hull is divided by ten bulkheads into watertight compartments such that the vessels are able to sustain hull damage up to eight meters in length without dangerous instability problems. For ship propulsion, one engine-room and the gear- room can be water-filled at the same time, and the frigates will still be able to proceed. The basic hull shape corresponds to that of a high-speed trawler. The frames in the bow and stern are very closely spaced. Amidships the thickness of the outer skin has been increased.
The propeller is protected against ice by a bulb in the stern. Brunvoll has a long tradition of supplying retractable azimuth units to navy and coast guard vessels. It started with delivery to the Norwegian Coast Guard's Andenes class in the late 70s, followed by tailor-made solutions for the Danish Navy's Thetis class in the 80s.
There are no bilge keels, but stabilisation is achieved by a combination of fin stabilizers from Blohm and Voss and a controlled passive tank system supplied by Intering. To minimise ice formation on the superstructure, all winches, capstans, etc. are placed under deck. The forecastle deck is trawler shaped and all open deck spaces and scuppers are heated. The allowed amount of icing is 375 tons.
The propulsion machinery consists of three MAN B&W V28/32 diesel engines with combined power of 9000 kW, fitted in two separate watertight compartments on each side of the gear compartment. The reduction gear box is able to operate under water. The fitted bow thruster is able to hold the bow against an athwartship wind of 28 knots. A retractable azimuth thruster is capable of propelling the ship at 10 knots, and can be considered as an emergency machinery set in case of damage to propeller or gears or total engine failure. A shaft generator of 1500 kW is located in the forward engine room, and there are three GM Detroit diesel motors with Volund Teknik generators, each with an output of 480 kW, installed with one in the forward and two in the aft engine room. An 127 kW emergency diesel generating set is fitted in a compartment under the forecastle deck. The ship has an endurance of 8300 nautical miles at varying speeds with a 10 per cent fuel reserve.
The Thetis type patrol vessels was equipped with a Lynx helicopter with an operational range of 2 hours or 200 km. However, the Lynx helicopters are being phased out with Seahawk helicopters with a higher level of capacity. The ships have undergone several conversions, the largest of which was carried out over the period 2014-2019. The ships were each at home in Denmark for two years to be rebuilt to be able to carry a Sikorsky MH-60R Seahawk helicopter, which was to take over the tasks on the Navy's ships after the aging Westland Lynx helicopter. At the same time, a new air and surface radar was installed, which meant that the characteristic ice block was removed. HDMS VÄDDEREN was the first to undergo the conversion and return to the North Atlantic in 2016, where it began training and procedure development with the new helicopter. Subsequently, HDMS HVIDBJØRNEN was completely rebuilt in 2017, HDMS THETIS in 2018, while HDMS TRITON was rebuilt by the end of 2019.
The MH-60R Seahawk has a larger operational range (3 hours or 230 nm) and can lift more weight than the Lynx helicopter. The Danish armed forces have ordered nine Seahawks from the US Navy to be delivered 2016-2018. The first three Danish Seahawks will be delivered in April 2016, while the last one, Romeo number 299, arrived in mid-2018.
Provisions cover 4 months' operations, and the stocks of spare parts are sufficient for 6 months at sea without replenishment. Helicopter fuel suffices for 150 flying hours. The frigate is ice strengthened and is able to proceed through 80 cm of solid ice. The hull has an icebreaking bow and stem lines suitable for operations in ice with only one propeller. Maximum continuous speed is 20 knots in four meter seas. The seakeeping qualities allow the ship to stand up to wind gusts of 150 knots during light ice conditions and operate in all sea conditions at speeds of 4-5 knots.
In several cases, inspection ships have also been used for tasks outside the Arctic area. The ships have, among other things, protected emergency aid ships in Africa, been a command ship for NATO's standing mine clearance forces and sailed around the world as an expedition ship during the great Galathea expedition in 2006-2007.
One and a half million people in Somalia depended on emergency aid from the UN food program WFP, but the supplies must be sailed through one of the world's most pirate-plagued waters. In 2007, three cargo ships carrying cargo for the WFP were attacked. It was also here that the crew of the Danish ship Danica White were held hostage for 88 days. Following a call from the UN to the international community to help protect maritime traffic, France decided for a period to allow a naval vessel to accompany the food ships.
Denmark took over the task from France in February 2008. The Danish frigate F 357 Thetis departed from Frederikshavn in Kenya's large port city of Mombasa, ready to scare pirates from blocking the food supply to war-torn Somalia. During the escort, there are soldiers from the special forces on board the cargo ship, and a pirate hardly gets so much as a foot on deck. An assault would be really bad business for the pirates, states operations officer Brian Larsen. Thetis will not actively chase the pirates, but by her mere presence deter them from attacking the food cargoes.
Part of the emergency aid enters via the port of Djibouti, and here Thetis can accompany it into the port. In other cities up the coast of Somalia, it must stay two nautical miles clear of land and here entrust the guarding to forces from the African Union, Armisa.
Despite far-reaching ambitions voiced by the Danish politicians and generous allocations to the military unseen since the Cold War-era, the Danish Armed Forces remain drastically understaffed. Within the Navy alone, the dramatic lack of staff led to Arctic patrols being put on pause for the crews to get the necessary rest. Instead of operating 24/7, Danish inspection ships admittedly to make do with patrolling during office hours alone, seeking port or dropping anchor at night.
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