alia ▁was ▁one ▁of ▁seven ▁s ▁built ▁for ▁the ▁ ▁( Ro yal ▁Italian ▁Navy ) ▁during ▁the ▁early ▁ 1 9 3 0 s . ▁ ▁Design ▁and ▁description ▁The ▁Arg onaut a ▁class ▁was ▁derived ▁from ▁the ▁earlier ▁s . ▁They ▁disp la ced ▁ ▁sur fac ed ▁and ▁ ▁sub mer ged . ▁The ▁sub mar ines ▁were ▁ ▁long , ▁had ▁a ▁beam ▁of ▁ ▁and ▁a ▁draft ▁of ▁. ▁They ▁had ▁a ▁oper ational ▁div ing ▁depth ▁of ▁. ▁Their ▁crew ▁number ed ▁ 4 4 ▁officers ▁and ▁en list ed ▁men . ▁ ▁For ▁surface ▁running , ▁the ▁boats ▁were ▁power ed ▁by ▁two ▁ ▁dies el ▁engines , ▁each ▁driving ▁one ▁prop eller ▁sh aft . ▁When ▁sub mer ged ▁each ▁prop eller ▁was ▁driven ▁by ▁a ▁ ▁electric ▁motor . ▁They ▁could ▁reach ▁ ▁on ▁the ▁surface ▁and ▁ ▁under water . ▁On ▁the ▁surface , ▁the ▁Set tem br ini ▁class ▁had ▁a ▁range ▁of ▁ ▁at ▁; ▁sub mer ged , ▁they ▁had ▁a ▁range ▁of ▁ ▁at ▁. ▁ ▁The ▁boats ▁were ▁armed ▁with ▁six ▁ ▁tor ped o ▁tub es , ▁four ▁in ▁the ▁bow ▁and ▁two ▁in ▁the ▁stern ▁for ▁which ▁they ▁carried ▁a ▁total ▁of ▁ 1 2 ▁tor ped o es . ▁They ▁were ▁also ▁armed ▁with ▁a ▁single ▁ ▁deck ▁gun ▁forward ▁of ▁the ▁con ning ▁tower ▁for ▁combat ▁on ▁the ▁surface . ▁Their ▁anti - air craft ▁arm ament ▁consisted ▁of ▁two ▁single ▁ ▁machine ▁guns