From 1960 "Tarmo" was the only state-owned steam-powered icebreaker in service. When the new diesel-electric "Tarmo" was commissioned in 1963, the old "Tarmo" was renamed "Apu" and handed over to the Finnish Navy. In 1964, she spent two months in Tallinn as an accommodation ship for the crews of "Riga" class frigates "Hämeenmaa" and "Uusimaa" that had been recently purchased from the Soviet Union. In 1966, "Apu" was handed back to the Finnish Maritime Administration and resumed her icebreaker duties until the commissioning of the next diesel-electric icebreaker, "Varma", in 1968. "Apu" was decommissioned in the following spring, but instead of scrapping her it was decided to turn the last Finnish steam-powered icebreaker into a museum ship. On 29 May 1969 she was moored at Hylkysaari next to the Helsinki Zoo and given back her original name. However, the retirement of "Tarmo" did not go as planned. The winter of 1970 turned out to be very harsh and the old icebreaker had to be recommissioned. After her propellers had been re-installed in the Suomenlinna drydock, "Tarmo" was again renamed "Apu" and ordered to the Archipelago Sea to escort icebound ships. However, her efforts were often described being "mostly of moral nature", and in the spring of 1970 she was returned to her moorings at Hylkysaari. When the new diesel-electric "Apu" was commissioned in the summer of 1970, it was certain that the old icebreaker could finally be retired. It took nearly 20 years until "Tarmo" was finally restored. In the 1970s and 1980s the Finnish Board of Navigation used its limited funding to maintain the ship in floating condition and the Maritime Historical Society of Finland tried to raise restoration funds, but despite the preservation efforts the wooden interior fittings and weather decks deteriorated over the years. When the Cabinet of Finland allotted two million Finnish markkas for the restoration of the old icebreaker, "Tarmo" was towed to Kotka in November 1990. After her interiors had been extensively documented and photographed, all fittings and furnishing were removed and stored ashore. When "Tarmo" was drydocked for inspection, her bottom plating was found out to be in surprisingly good condition.