▁man eu ver ability ▁of ▁the ▁ice bre aker ▁— ▁the ▁tact ical ▁diameter ▁of ▁the ▁turning ▁circle ▁in ▁open ▁water ▁is ▁less ▁than ▁the ▁overall ▁length ▁of ▁the ▁ship . ▁This ▁is ▁especially ▁useful ▁during ▁esc ort ▁and ▁assistance ▁operations ▁in ▁difficult ▁ice ▁conditions ▁when ▁the ▁ice bre aker ▁has ▁to ▁operate ▁at ▁close ▁proxim ity ▁to ▁other ▁vessels ▁at ▁low ▁spe eds . ▁T ogether ▁with ▁three ▁ 1 , 1 5 0 - k W ▁Brun vol l ▁F U - 8 0 - LT C - 2 0 0 0 ▁variable - p itch ▁bow ▁thrust ers ▁the ▁az im uth ▁thrust ers ▁also ▁allow ▁dynamic ▁position ing ▁during ▁off sh ore ▁operations . ▁The ▁bow ▁thrust ers ▁are ▁not ▁used ▁in ▁ice . ▁ ▁The ▁maximum ▁speed ▁of ▁Bot nica ▁is ▁ ▁in ▁open ▁water ▁and ▁she ▁can ▁maintain ▁a ▁speed ▁of ▁ ▁in ▁ ▁ice . ▁The ▁maximum ▁ice ▁thick ness ▁in ▁which ▁the ▁vessel ▁is ▁capable ▁of ▁maintain ing ▁constant ▁speed ▁is ▁. ▁Her ▁b oll ard ▁pull ▁is ▁ 1 1 7 ▁tons . ▁ ▁History ▁ ▁Development ▁and ▁construction ▁▁ ▁The ▁development ▁of ▁the ▁Finn ish ▁multip ur pose ▁ice break ers ▁began ▁in ▁the ▁mid - 1 9 8 0 s ▁when ▁the ▁Finn ish ▁National ▁Board ▁of ▁Navigation ▁launched ▁a ▁project ▁to ▁find ▁secondary ▁uses ▁for ▁the ▁new ▁vessels ▁it ▁was ▁planning ▁to ▁build ▁as ▁a ▁replacement ▁for ▁some ▁of ▁the ▁oldest ▁ice break ers . ▁Until ▁then ▁the ▁Finn ish ▁ice