üt ze , ▁U - 2 5 ▁had ▁no ▁success ▁during ▁Hart mut . ▁ ▁U - 4 6 ▁- ▁a ▁Type ▁VII B ▁under ▁Herbert ▁So h ler ▁with ▁I W O ▁Er ich ▁To pp . ▁U - 4 6 ▁had ▁no ▁success ▁during ▁Hart mut . ▁ ▁U - 5 1 ▁- ▁a ▁Type ▁VII B ▁under ▁Diet rich ▁Kn orr , ▁who ▁failed ▁to ▁sink ▁any ▁vessels ▁during ▁Hart mut . ▁▁ ▁- ▁a ▁Type ▁IX B ▁under ▁Georg - Wil helm ▁Schul z . ▁U - 6 4 ▁was ▁the ▁first ▁U - bo at ▁s unk ▁by ▁aircraft ▁in ▁the ▁war . ▁While ▁anch ored ▁near ▁B j erk vik , ▁British ▁forces ▁including ▁a ▁F aire y ▁S word fish ▁launched ▁from ▁ ▁s ank ▁the ▁boat ▁on ▁ 1 3 ▁April . ▁Schul z ▁and ▁other ▁surv iving ▁crew ▁were ▁res cu ed ▁from ▁the ▁water ▁by ▁German ▁troops ▁in ▁Norway . ▁▁ ▁- ▁a ▁Type ▁IX B , ▁which ▁pat rolled ▁in ▁the ▁North ▁Sea ▁for ▁ 3 6 ▁days ▁without ▁s inking ▁any ▁ships . ▁ ▁U - Bo at ▁Group ▁Two ▁Pat rol ▁Area : ▁Tr ond heim , ▁N ams os , ▁R oms d als f j ord ▁ ▁U - 3 0 ▁- ▁a ▁Type ▁VII A ▁under ▁Fritz - Jul ius ▁L emp , ▁who ▁was ▁responsible ▁for ▁s inking ▁the ▁, ▁the ▁first ▁ship ▁s unk ▁during ▁the ▁war . ▁His ▁pat rol ▁along ▁the ▁coast ▁of