UR I1 Rev2 CLN
UR I1 Polar Class Descriptions and Application - Rev.2 Apr 2016
UR I2 Rev3 CLN
UR I2 Structural Requirements for Polar Class Ships - Rev.3 Apr 2016 Clean
Note: UR I2 Rev.4 will come into force on 1 January 2021 and can be found in "Revision History"
UR I3 Rev1 Corr1 CLN
UR I3 Machinery Requirements for Polar Class Ships - Rev.1 Corr.1 Oct 2007