▁ 1 9 9 2 . ▁The ▁ ▁ships ▁had ▁large ▁open ▁a ft ▁de cks ▁similar ▁to ▁platform ▁supply ▁vessels ▁and ▁their ▁two ▁ 7 , 5 0 0   k W ▁dies el - elect ric ▁Aqu am aster ▁Z - drive ▁az im uth ▁thrust ers ▁provided ▁dynamic ▁position ing ▁cap ability . ▁The ▁first ▁Finn ish ▁multip ur pose ▁ice bre aker , ▁F enn ica , ▁was ▁delivered ▁in ▁ 1 9 9 3 ▁and ▁her ▁sister ▁ship , ▁Nord ica , ▁in ▁the ▁following ▁year . ▁ ▁The ▁third ▁multip ur pose ▁ice bre aker ▁Bot nica ▁was ▁designed ▁mainly ▁for ▁G ulf ▁of ▁Finland ▁esc ort ▁ice bre aking . ▁Its ▁summer ▁tasks ▁were ▁planned ▁in ▁co operation ▁with ▁D S ND ▁Off sh ore ▁AS , ▁and ▁the ▁discussion ▁led ▁to ▁the ▁conclusion ▁that ▁this ▁type ▁of ▁vessel ▁could ▁be ▁used ▁as ▁a ▁cost - effect ive ▁alternative ▁to ▁semi - sub mers ible ▁platforms ▁for ▁North ▁Sea ▁operators . ▁The ▁new ▁light ▁well ▁inter vention ▁and ▁sl im ▁hole ▁dr illing ▁tasks ▁brought ▁in ▁extra ▁safety ▁requirements , ▁including ▁explos ion ▁proof ▁main ▁deck ▁arrangement ▁and ▁A - class ▁bulk head ▁against ▁deck house ▁and ▁lif es aving ▁equipment ▁because ▁of ▁a ▁blow ▁out ▁risk . ▁The ▁vessel ▁was ▁designed ▁into ▁highest ▁redundant ▁D P ▁class , ▁with ▁also ▁mach in ery , ▁thr uster ▁and ▁D P ▁control ▁rooms ▁divided ▁into ▁two ▁independent ▁spaces . ▁A ▁moon ▁pool ▁was ▁designed ▁in ▁the ▁vessel