The 51 meter long and 250 ton Hamina-class fast attack craft were originally delivered in the years around 2000, and have generally been seen as a successful class given their somewhat unique concept of operation with a focus on surface combat staged from the cluttered Finnish archipelagos – emphasising manoeuvrability, shallow draught, and good firepower at the cost of somewhat limited endurance and small crew.
A changed security landscape has however seen shifting priorities for the Finnish Navy, and while the limited endurance and poor suitability to operations in ice remain, the vessels have become more balanced and efficient overall following the upgrade. A key part of this is the emphasis on underwater warfare. This include the first torpedoes fielded by the Finnish Navy in decades, as the vessels are equipped with the Swedish light TP 47-system (Saab Lightweight Torpedo, SLWT) which is a dedicated littoral anti-submarine weapon. With the first Finnish firings of the new weapon having taken place only this year, the Navy has been able to loan older TP 45-torpedoes from the Swedish Navy to allow for training and covering the period until stocks of the brand-new torpedo have reached adequate sizes.
In addition to these, the sensor suite for underwater warfare has been significantly upgraded with Kongsberg ST2400 variable depth sonars. The ST2400 is a medium-frequency sonar designed with an emphasis on shallow waters. This includes rapid deployment and the ability to take high speed manoeuvres, ensuring omnidirectional operations in challenging acoustic environments without limiting the vessels manoeuvrability.
Another major upgrade to the Hamina-class is the replacement of the anti-ship Saab RBS 15 with new IAI Gabriel V missiles (although none of the four ships in the class have been spotted fitted with the new missiles yet). While much about the missile is shrouded in secrecy, it is known that they feature significantly more range, as well as a secondary land attack-capability. The weapon is set to become the new standard anti-ship missile for the Finnish Navy, and will equip the upcoming Pohjanmaa-class (Squadron 2020) and truck-based coastal defence batteries as well.
The Umkhonto-IR missiles remain the primary self-defence anti-aircraft weaponry, but have received an unspecified upgrade as well. The Saab Trackfire remote-weapon station has also replaced pintle-mounted heavy machine guns. To compensate for the increase in weight, the 57 mm Bofors main gun of the vessels have been replaced by a lighter 40 mm Mk4 naval gun from the same manufacturer. The four 57 mm guns will in turn be reused on the Pohjanmaa-class.
However, an important change is also found inside the vessels, as the combat management system has been switched from the Atlas Elektronik ANCS to Saab 9LV. This reflects the general idea under which many key systems will be the same between the reworked Hamina- and the upcoming Pohjanmaa-class, to allow for synergies when it comes to training, maintenance, logistics, and concepts of operations. Under the new configuration, the vessel are expected to serve into the 2030’s.
