The fourth boat was ordered on 21 May 2007 to be called 'Audacious'.

In October 1946, the first two boats were ordered.

The fourth boat was ordered in 2007, with boats number 5 and 6 being authorised in April 2010.

These boats had been ordered during the Winter War in 1940, but due to lack of material, the production took time, and became ready by 1943.

The boat was ordered to return to base.

The remaining boat was taken out of service for fear of a repeat disaster, and new German boats were ordered.

Two more boats were ordered in 1916, bringing the class total to eight.

The boats were ordered in the 1904 emergency programme.

Nevertheless 14 more boats of the class were ordered on 29 June 1918 for delivery in 1919.

The remaining 10 boats were ordered as part of the 1904-05 Programme.