Ice navigation vessel or Ice-strengthened vessel is a class of ships specially prepared for independent ice navigation in the waters of the polar seas and for following icebreakers in especially difficult ice conditions.[1][2] Various registration authorities assign ice classes to vessels based on their technical characteristics.[3][4] Due to this, ice navigation vessels are usually referred to as ice-class vessels without indicating which class they belong to, but indicating the type of vessel (e.g. ice-class tanker, ice-class cargo ship etc).[5]
myvessellogs
was invoked but never defined (see the help page).