Flyvefisken-class patrol vessel

The Flyvefisken-class patrol vessels ("Flying fish" in Danish) are warships of the Royal Danish Navy. The class is also known as the Standard Flex 300 or SF300 class. The five vessels sold to the Portuguese Navy are locally referred as Tejo class.

Flyvefisken class P555 Støren
P555 HDMS Støren
Class overview
NameFlyvefisken class
SubclassesTejo class (Portugal)
In commission1989–present
Preserved3 (for sale)
General characteristics [1]
TypePatrol vessel
  • 320 tonnes (315 long tons) light
  • 450 tonnes (443 long tons) full load
Length54 m (177 ft 2 in)
Beam9 m (29 ft 6 in)
Draught2.5 m (8 ft 2 in)
  • 30 knots (56 km/h; 35 mph) on turbine + diesels
  • 20 knots (37 km/h; 23 mph) on MTU's
  • 7 knots (13 km/h; 8.1 mph) on hydraulic drive
Range3,860 nmi (7,150 km) at 18 kn (33 km/h; 21 mph)
Complement19-29 depending on role
Sensors and
processing systems
  • Terma Scanter Mil 009 surveillance radar
  • Thales TMS 2640 Salmon variable depth sonar
  • Furuno navigational radar
  • EADS TRS-3D air search radar (Combat role)
  • Plessey AWS-6 air search radar (MCM role)
  • Saab 9LV 200 Mk 3 Fire control radar
HDMS Viben (P562).
LVS Dzūkas (P12).

Containerised weapon systems edit

The Flyvefisken ships were constructed using an innovative modular design known as StanFlex: they have a standard hull in which containerised weapons or systems can be placed. This allows them to rapidly change roles, typically in 48 hours. This enables the ships to be configured to perform the following roles:

  • Surveillance/pollution control
  • Combat
  • Mine countermeasures/minehunter (MCM)
  • Minelayer

The containers measure 3.5 by 3 by 2.5 metres (11.5 ft × 9.8 ft × 8.2 ft). One container is situated on the foredeck; the other three go on the quarterdeck behind the superstructure and funnel. Furthermore the ships are built using the sandwich principle - a layer of fiberglass either side of a core of PVC cell foam. This forms the structure from keel to top of mast. This building method reduces maintenance costs - so much so that 20 years later the new Diana and -Holm class have been built using the same materials.[2]

Replaced three different vessels edit

The Flyvefisken class replaced three different vessels in the Danish Navy: Six torpedo boats of the Søløven class (1965–90), six coastal minesweepers of the Sund class (1955–99) and eight seaward defence craft of the Daphne-class (1961–91). It was possible because of the containerised systems and modern technology.

The replaced vessels used World War II (or World War I) tactics: The Søløven boats were light plywood boats propelled by three turboshafts, which attacked the enemy ships with torpedoes in 54-knot (100 km/h; 62 mph) hit-and-run attacks. The Flyvefisken class is not that fast, but their Harpoon missiles are sufficient for the task.

The Sund-class minesweepers were built of wood, bronze and other non-magnetic materials. They swept mine fields by trawling through the area with paravanes on tow separating magnetic and acoustic generators for the bottom mines, and chain cutters for the horned mines. The Flyvefisken class is a minehunter and locates the mines with side-scan sonar and neutralizes them one by one with a ROV.

The Daphne class attacked submarines by dropping depth charges to a preselected depth, while sailing past the submarine. The Flyvefisken class fights submarines with anti-submarine homing torpedoes.

Vessels in Portuguese Service edit

Four vessels of the class (Glenten, Ravnen, Skaden and Viben) were acquired by the Portuguese Navy in 2010 and re-named Mondego, Douro, Guadiana and Tejo. A fifth vessel, Gribben, was also acquired by the service as a spare parts hull. After a period of upgrade and reconfiguration, Mondego and Tejo were specifically tasked to police Portugal's exclusive economic zone around Madeira.

In 2023, 13 sailors assigned to Mondego were relieved of their duties when they refused to board the ship claiming her to be unseaworthy. The navy rejected the claim, which was made after the vessel had been tasked to monitor a Russian ship sailing in the vicinity of Madeira.[3][4]

Ships in class edit

A total of 14 ships were built in the class, in three series:

# Name Laid down Launched Commissioned Decommissioned Int. Callsign Role
Series 1
P550 Flyvefisken
(Flying fish)
15 August 1985 26 April 1986 19 December 1989
Sold to Lithuania, March 2007 - LVS Žemaitis (P 11)
P551 Hajen
February 1988 6 August 1989 19 August 1990
Sold to Lithuania, March 2007 - LVS Dzūkas (P 12)
P552 Havkatten
August 1988 13 January 1990 1 November 1990 12 January 2012 -
Sold to Lithuania, 23 November 2016 - LVS Sėlis (P 15)
P553 Laxen
March 1988 20 May 1990 12 March 1991 7 October 2010 OVDD MCM
P554 Makrelen
December 1988 8 January 1991 4 October 1991 7 October 2010 OVDE MCM
P555 Støren
August 1989 1 September 1991 24 April 1992 7 October 2010 OVBF MCM
P556 Sværdfisken
- 1 September 1991 1 February 1992 2 August 2006, scrapped OVDG MCM
Series 2
P557 Glenten
- 1992 1 February 1992 7 October 2010
Sold to Portugal, October 2014 - NRP Mondego (P 592)
OVDH Combat
P558 Gribben
- 1992 1 July 1993 7 October 2010
Sold to Portugal, October 2014 - as spare parts hull
OVDI Surveillance
P559 Lommen
- 1993 21 January 1994
Sold to Lithuania, March 2007 - LVS Aukštaitis (P 14)
OVDJ Surveillance
P560 Ravnen
- 1994 7 October 1994 7 October 2010
Sold to Portugal, October 2014 - NRP Douro (P 591)
OVDK Combat
P561 Skaden
(European magpie)
- 1994 10 April 1995 7 October 2010
Sold to Portugal, October 2014 - NRP Guadiana (P 593)
OVDL Combat
P562 Viben
(Northern lapwing)
- 1995 15 January 1996 7 October 2010
Sold to Portugal, October 2014 - NRP Tejo (P 590)
OVDM Combat
Series 3
(Sea lion)
- 1995 27 May 1996 - OVDN Surveillance
Diving support from 2012

The difference between the series is mainly in the configuration of the propulsion system. Series 2 is not equipped with hydraulic propulsion, but instead has an additional auxiliary engine, and Series 3 has one further auxiliary engine.

References edit

  1. ^ "Specifications: Flyvefisken Class (SF 300) Multi-Role Vessels - Naval Technology". Retrieved 2009-11-26.
  2. ^ "Flyvefisken Class (SF 300) Multi-Role Vessels - Naval Technology". Retrieved 2009-11-26.
  3. ^ "Portuguese Navy Relieves Sailors for Refusing to Board "Faulty" Vessel". The Maritime Executive. 17 March 2023. Retrieved 26 July 2023.
  4. ^ "NRP MONDEGO". Portuguese Navy. Retrieved 24 July 2023.

External links edit