The icebreaker Tarmo in the Helsinki harbour in 1925

Here is a nice shot of the famous Finnish icebreaker Tarmo assisting ships in the port of Helsinki in the winter of 1925.

Tarmo was the most powerful Finnish icebreaker in the first decades of the 20th century. Its two coal fired engines produced a combined 3850 hp. In 1951 oil replaced coal as fuel for the ships engines. 

Tarmo, which was launched in 1907, was built by the W.G. Armstrong & Co Ltd. , Walker Shipyard in Newcastle, was in active service until 1970. She is currently moored at Maritime Museum of Finland in Kotka, Finland.

The 67,1 x 14,3m Tarmo has a displacement of 2300 tons. (image by wikipedia)

Tarmo is the second oldest icebreaker surviving in the world. Only the Russian icebreaker Angara, also now serving as a floating museum, is a few years older.

PS

This 1925 picture of a cargo ship in a Finnish harbour shows why Tarmo and the other icebreakes were needed: