ater p ill ars ▁resulted ▁in ▁the ▁very ▁unusual ▁engine ▁arrangement . ▁While ▁having ▁a ▁large ▁number ▁of ▁smaller ▁engines ▁increases ▁the ▁flex ibility ▁and ▁efficiency ▁of ▁the ▁power ▁system ▁— ▁engines ▁can ▁be ▁started ▁and ▁stopped ▁on ▁demand ▁and ▁the ▁running ▁engines ▁operate ▁at ▁maximum ▁efficiency ▁— ▁the ▁main ▁engines ▁of ▁Bot nica ▁require ▁consider ably ▁more ▁maintenance ▁hours ▁in ▁comparison ▁to ▁ships ▁with ▁fewer ▁generating ▁sets . ▁The ▁fuel ▁consumption ▁of ▁the ▁main ▁engines ▁at ▁maximum ▁dra ug ht ▁is ▁ 5 0 ▁tons ▁of ▁marine ▁dies el ▁oil ▁( M DO ) ▁per ▁day ▁at ▁full ▁power , ▁ 2 5 ▁tons ▁at ▁a ▁service ▁speed ▁of ▁, ▁ 1 0 – 1 5 ▁tons ▁during ▁dynamic ▁position ing ▁and ▁ 4 ▁tons ▁at ▁port . ▁ ▁Design ed ▁according ▁to ▁the ▁power ▁plant ▁principle ▁in ▁which ▁the ▁main ▁engines ▁produce ▁power ▁for ▁all ▁ship board ▁consum ers , ▁Bot nica ▁has ▁no ▁separate ▁auxili ary ▁gener ators . ▁However , ▁there ▁is ▁a ▁smaller ▁six - cy l inder ▁C ater p ill ar ▁ 3 4 0 6 ▁as ▁an ▁emer gency ▁dies el ▁generator ▁with ▁an ▁output ▁of ▁. ▁ ▁Bot nica ▁was ▁one ▁of ▁the ▁first ▁ice break ers ▁to ▁be ▁equ ipped ▁with ▁Az ip od ▁prop ulsion , ▁A BB ' s ▁brand ▁of ▁electric ▁az im uth ▁thrust ers ▁developed ▁in ▁Finland . ▁The ▁two ▁ 5 ▁M W ▁Az ip od ▁VI 1 6 0 0 A ▁units ▁consider ably ▁improve ▁the