The main peacetime mission of the navy (Merivoimat), together with the coast guard, was to conduct surveillance of territorial waters and fishing zones and to identify violators. During a crisis situation or hostilities, the navy would be called upon to prevent unauthorized use of Finland's territorial waters, to protect vital sea routes and maritime traffic, and to close off its most important ports. Treaty obligations and strategic concerns made securing the demilitarized Aland Islands a key wartime mission of the navy. This it would do with the help of the army, coast artillery, and the coast guard. If faced by an amphibious attack, the navy's objective would be to wear down the aggressor and to restrict his operations.
Naval tasks would be carried out in an integrated manner with the army coast artillery and the air force. The shallow waters of the coastline, broken by an extensive archipelago, would facilitate the laying of defensive mines, which would figure importantly in defense against seaborne invasion. Although the fleet units were limited in size and in weaponry, their maneuverability and missile-based firepower could inflict damage on a hostile force operating in Finnish waters and in adjacent sea areas. The precise form in which a naval threat might develop was unclear, because a Soviet invasion by sea was unlikely and Western ships would be directly exposed to Soviet naval strength in the Baltic, in the event of general conflict. By providing for control over its own coastal waters, however, Finland hoped to convince the Soviets that the Gulf of Finland would be secure and that the approaches to Leningrad would not be left unguarded.
Under the 1947 Treaty of Paris, naval manpower strength was limited to 4,500. In addition to the overall limit of 10,000 tons, the navy was not permitted to operate submarines or torpedo boats. As of 1988, active naval personnel numbered only 2,700, of whom 1,300 were conscripts. The largest vessels were two small corvettes of 660 tons, each armed with 120mm guns and antisubmarine rocket launchers. Eight missile boats were armed with Swedish and Soviet ship-to-ship missile systems. Four more missile boats were due to be delivered in the early 1990s. These boats were supported by inshore patrol craft, together with minelaying and minesweeping vessels (see table 23, Appendix A).
In peacetime the main naval units were organized into gunboat, missile boat, and mine warfare flotillas. Under wartime conditions, they would be organized into task forces with a mix of vessels as required for specific operations. The wartime task forces would be directed by the navy commander in chief and would be part of the general forces. Naval assets operating with the coast artillery would be directed by the commander of the military area in which they were located and would form part of the local forces. All three flotillas were based at the navy's operational headquarters at Pansio, near Turku in the southwest, where an archipelago with few navigable channels, guarded by coastal fortifications, would present great obstacles to an intruding naval force. The gunboat flotilla consisted of one corvette as a command ship and the ten Tuima class missile boats and Nuoli class fast attack craft. The missile squadron consisted of the other corvette and the four Helsinki class missile boats. The mine warfare squadron was made up of the minelayers and minesweepers. A patrol flotilla, based at Helsinki, operated the Ruissalo and Rihtniemi class attack craft.
Owing to a serious manpower shortage, only about half of the fleet was manned and operational under peacetime conditions. The readiness of the remaining ships was reportedly maintained at an adequate level by keeping them heated, by frequently testing their systems, and by rotating them into active service.
During a period of crisis or conflict, the Coast Guard, which was part of the RVL, would be integrated into the navy. Several of its larger patrol craft of the Tursas and Kiisla class were fitted with antisubmarine warfare weapons. A large number of patrol boats were equipped with submarine tracking gear.
Data as of December 1988