▁ 1 2 mm ▁of ▁arm or ▁on ▁its ▁“ cit adel ” ▁protect ing ▁the ▁engines ▁and ▁other ▁vit als . ▁While ▁drawing ▁more ▁water ▁than ▁a ▁half - meter , ▁it ▁still ▁could ▁operate ▁in ▁very ▁shall ow ▁waters ▁as ▁it ▁only ▁drew ▁ 0 . 8 0 ▁meters . ▁ ▁The ▁smaller ▁version , ▁known ▁as ▁B K A ▁ 1 1 2 5 , ▁only ▁drew ▁ 0 . 5 ▁meters ▁and ▁disp la ced ▁ 2 9 ▁tons . ▁These ▁were ▁only ▁slightly ▁shorter ▁( 2 2 . 6 ▁meters ) ▁but ▁had ▁less ▁arm or ▁protection . ▁ ▁Series ▁production ▁began ▁in ▁ 1 9 3 5 ▁at ▁small ▁ship y ards ▁along ▁the ▁Soviet ▁Union ’ s ▁in land ▁rivers , ▁ ▁World ▁War ▁II ▁By ▁the ▁time ▁of ▁the ▁ 1 9 4 1 ▁invasion ▁by ▁Germany , ▁ 8 5 ▁boats ▁had ▁been ▁delivered ▁with ▁ 6 8 ▁more ▁under ▁construction . ▁They ▁went ▁into ▁action ▁very ▁early , ▁with ▁boats ▁of ▁the ▁Dan ube ▁fl ot illa ▁in fil tr ating ▁Roman ian ▁def enses ▁to ▁land ▁troops ▁on ▁ 2 4 ▁June ▁and ▁routing ▁Roman ian ▁mar ines ▁def ending ▁the ▁Dan ube ▁delta . ▁Don ▁During ▁the ▁Third ▁Reich ▁era , ▁the ▁D DS G ▁was ▁involved ▁in ▁transport ing ▁Jews ▁after ▁Krist all n acht . ▁ ▁In ▁ 1 9 9 1 ▁the ▁company ▁was ▁divided ▁up ▁with ▁a ▁cargo ▁sh ipping ▁enter prise ▁and ▁a ▁passenger ▁le is