▁the ▁U B ▁I ▁design ▁called ▁for ▁a ▁boat ▁about ▁ ▁long ▁and ▁disp la cing ▁about ▁ ▁with ▁two ▁tor ped o ▁tub es . ▁U B - 4 ▁was ▁part ▁of ▁the ▁initial ▁all ot ment ▁of ▁eight ▁sub mar ines — number ed ▁ ▁to ▁— ordered ▁on ▁ 1 5 ▁October ▁from ▁Germania wer ft ▁of ▁K iel , ▁just ▁sh y ▁of ▁two ▁months ▁after ▁planning ▁for ▁the ▁class ▁began . ▁ ▁U B - 4 ▁was ▁laid ▁down ▁by ▁Germania wer ft ▁in ▁K iel ▁on ▁ 3 ▁November . ▁As ▁built , ▁U B - 4 ▁was ▁ ▁long , ▁ ▁ab e am , ▁and ▁had ▁a ▁draft ▁of ▁. ▁She ▁had ▁a ▁single ▁ ▁Da im ler ▁ 4 - cy l inder ▁dies el ▁engine ▁for ▁surface ▁travel , ▁and ▁a ▁single ▁ ▁S iem ens - Sch uck ert ▁electric ▁motor ▁for ▁under water ▁travel , ▁both ▁attached ▁to ▁a ▁single ▁prop eller ▁sh aft . ▁Her ▁top ▁spe eds ▁were ▁, ▁sur fac ed , ▁and ▁, ▁sub mer ged . ▁At ▁more ▁moder ate ▁spe eds , ▁she ▁could ▁sail ▁up ▁to ▁ ▁on ▁the ▁surface ▁before ▁ref uel ing , ▁and ▁up ▁to ▁ ▁sub mer ged ▁before ▁re charg ing ▁her ▁batter ies . ▁Like ▁all ▁boats ▁of ▁the ▁class , ▁U B - 4 ▁was ▁r ated ▁to ▁a ▁div ing ▁depth ▁of ▁, ▁and ▁could ▁completely ▁sub merge ▁in ▁ 3 3 ▁seconds . ▁ ▁U