Finnish navy minelayer Keihässalmi 1958-1992

Keihässalmi returning from drydock in 2019. She’s no longer in seaworthy condition, so the ship was towed to and from the drydock. Photo: Jorma Kontio/Forum Marinum

With our gratitude to our guest writer who also provided the photos: 

Heikki Laurila

heikki.laurila@forum-marinum.fi 

Writer in assistant curator at Forum Marinum Maritime Center working on history of the Finnish Navy.

Naval mines are an effective and relatively inexpensive weapon system. Minefields can deny the opponent the ability to exploit a particular sea area, close shipping lanes or protect important targets from invasion. Finland’s rugged and rather shallow coast is well-suited for using mines, and mines have been one of the main weapon systems of the Finnish Navy from it’s very beginning. Naval mines played a major role in naval warfare in the Baltic sea and Gulf of Finland: Approximately 60 000 mines were laid by the German, Finnish and Soviet navies into the Gulf of Finland Alone.

In 1950’s the Finnish Navy started it’s reconstruction program to replace the losses suffered during the war. First major newbuild was the minelayer Keihässalmi, which was commissioned in 1958. She was built to replace minalayer Riilahti lost in 1943. The two minelayers share a similar layout, but with a displacement of  360 tons Keihässalmi is slightly larger than her predecessor. Ship is 56 meters long, beam is 7,7 m and draught 2,2 meters. When commissioned Keihässalmi was powered by two MAN diesels but later they were replaced with two Wärtsilä diesel engines with 1200 Kw in total. Maximum speed was around 15 knots and she had a crew of 60. Despite being built in the 1950's Keihässalmi represents wartime design and construction methods of ships.

Upon completion she formed the core of the Finnish Navy’s mine-laying capability with minelayer Ruotsinsalmi, the sistership of  the aforementioned Riilahti. Naval mines were her main weapon system and  peacetime mission was to maintain readiness to conduct mining operations. Another important task was to train conscripts as they formed the major part of the ship’s crew The conscripts were taught seamanship but also trained to operate the mines, artillery and anti-submarine weapons.

 

This view from the stern illustrates the layout of the mine deck. Loaded on the middle track are contact mines type S/41 and S/43 and on the left is an influence mine bought from the Soviet Union in 1980’s. An AK-230 gun is seen atop of the platform. Photo: Jorma Kontio/Forum Marinum 

The mines were carried on an open mine deck on three sets of rails. The anchors of the mines had wheels, so the mines could be pushed and pulled along the rails. For loading and handling of the mines ship had a crane. This allowed mines to be loaded in remote locations that had no infrastructure for handling the mines. With a crane the mines could also be loaded from barges.  

Keihässalmi could carry up to 100 mines, but the amount carried depended on the size of the mine. Early in her career Keihässalmi operated mainly with traditional contact mines like S/41 that had seen service during the war. S/41  had a charge of 200 kg and could be anchored to sea up to 100-200 meter deep. It’s operational depth was from 0,5 meters to 50 meters. In addition to mines Keihässalmi was able to conduct minesweeping with it’s mechanical sweeper: It was made of Y-shaped wiring with floats and cutters to cut the mooring lines of the mines.

The bottom of Keihässalmi was flat like a barge.  This, coupled with a low draught, made the vessel ideal for navigating in the shallow channels of the archipelago. However, during storms in the open sea, the vessel rocked drastically. In this photo Keihässalmi is fetching a detached target raft off the coast of Pori in the 1980s. 

A minelayer is very vulnerable when carrying a full load of mines and it’s an attractive target to the enemy. Therefore mining operations were planned to be conducted in secrecy to protect the vessel and prevent detection of the minefields by the enemy. To protect the ship from detection the Finnish Navy experimented with various paint schemes to camouflage the ship. The plan was to keep the ship hidden in daytime by hiding it in a natural harbour with camouflage and nets blending the ship into its surroundings. There the ship could wait for cover of darkness to conduct her mining operations.

When commissioned she had three 40 mm Bofors guns. But as the Finnish Navy lacked ships with heavy artillery it was once tested if a 75 mm could be placed on the foredeck. The test was not successful as the ship’s structures were too weak to withstand gun’s recoil. Later the Bofors guns were replaced by two Soviet-built 30 mm AK-230 twin guns with fire control radar. In addition to those guns, the ship had two 20 mm Madsen machine cannons onboard.

 

The sailing season of Keihässalmi lasted from spring until the seas froze in winter and the crew working on mines were exposed to the elements.  Photo: Forum Marinum archives 

The ship has a rich history and her crew has many stories to tell. Some of those stories have been recorded, and here I give you an example of daily life onboard the Keihässalmi in 1980’s. During the winter the ship was moored at the navy base in Turku as Keihässalmi was not strengthened to operate in ice. A story says that sometime in 1980’s the ship had a major rat problem, as they had come onboard from a merchant ship docked at a shipyard nearby. The commanding officer mobilized the conscripts to hunt down the rats and promised conscripts  one performance vacation day for each rat captured. Sailors had to present a tail of a rat to prove their kill. One of the conscripts lived on a farm so he brought back a set of tails from rats he had captured during the weekend. He earned his extra holidays, but when the commanding officer heard about the ruse he changed the rules. From that on a complete rat had to be presented to earn the reward. Once again the crew proved to be innovative, as they killed a rat and put it into the freezer. A conscript could melt the rat and use it to earn vacation, but after each use it was returned to the freezer to wait for the next user.

Keihässalmi was decommissioned in 1992 and replaced by two new Hämeenmaa-class minelayers. In 1994 she was opened as a museum ship in Turku and currently she’s one of the museum's ships moored at Forum Marinum Maritime Center. Ship is open to the public during summer months.