Flyvefisken-class (Standardflex 300 or SF300)

Summary

Description

The Flyvefisken-class patrol vessels, translated as "Flying fish" from Danish, are warships of the Royal Danish Navy recognized also as the Standard Flex 300 or SF300 class. Following their service in Denmark, certain vessels of this class saw their future with the Portuguese Navy, where they were designated as the Tejo class.

The unique aspect of the Flyvefisken-class is the innovative modular design known as StanFlex. This design incorporates the flexibility of rapidly interchangeable containerized weapons or systems within a standard hull, facilitating the swift transition of operational roles such as surveillance/pollution control, combat, mine countermeasures/minehunter (MCM), and minelayer typically within 48 hours. The containers utilized for such role changes are specifically sized to fit designated spots on the ship, with one on the foredeck and three on the quarterdeck.

The construction method employed for these ships also stands out due to its sandwich principle, which uses layers of fiberglass surrounding a core of PVC cell foam. This technique extends from the keel to the mast's top, offering a robust structure that significantly reduces maintenance costs—an advantage reflected in subsequent Danish naval vessels like the Diana and Holm class.

The introduction of the Flyvefisken class revolutionized certain fleet segments of the Danish Navy by replacing 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). With their containerized systems and advanced technology, these new ships could successfully supersede the older vessels that relied on strategies from the World Wars. The Flyvefisken-class ships may not possess the same speed as their predecessors, but their armament, such as the Harpoon missiles and anti-submarine homing torpedoes, is strategically sufficient for modern-day naval tasks.

In terms of operational history, the class has seen its share of instances, particularly within the Portuguese Navy, which acquired four vessels (Glenten, Ravnen, Skaden, and Viben) that were upgraded, renamed, and deployed to secure Portugal's exclusive economic zone around Madeira. However, in 2023, the Mondego became a subject of contention when 13 sailors were relieved of their duties after refusing to board the vessel, which they claimed was unseaworthy, a claim that the navy rejected.

The Flyvefisken-class has a total of 14 built ships, differentiated across three series mainly through variations in propulsion configuration. The second series lacks hydraulic propulsion, while the third series contains an additional auxiliary engine, indicating enhancements as the series progressed.

Technical specifications