- 5 0 ▁- ▁a ▁Type ▁VII B ▁was ▁s unk ▁by ▁mines ▁on ▁ 6 ▁April ▁en ▁route ▁to ▁her ▁pat rol ▁area . ▁ ▁U - Bo at ▁Group ▁Six ▁Pat rol ▁Area : ▁Pent land , ▁Or k ney ▁islands , ▁Sh et land ▁Islands ▁ ▁U - 1 3 ▁- ▁a ▁Type ▁II B ▁commanded ▁by ▁Max - Martin ▁Schul te . ▁She ▁s ank ▁two ▁ships ▁and ▁dam aged ▁another ▁during ▁the ▁oper ational ▁time ▁period . ▁During ▁this ▁pat rol , ▁U - 1 3 ▁dock ed ▁in ▁recently ▁occupied ▁Ber gen ▁for ▁a ▁short ▁time ▁on ▁ 1 9 ▁to ▁ 2 1 ▁April . ▁ ▁U - 5 7 ▁- ▁a ▁Type ▁II C ▁under ▁Cla us ▁K orth . ▁U - 5 7 ▁s ank ▁a ▁British ▁tank er ▁in ▁late ▁March , ▁but ▁had ▁no ▁success ▁during ▁Wes er üb ung . ▁ ▁U - 5 8 ▁- ▁a ▁Type ▁II C ▁under ▁Herbert ▁K upp isch ▁had ▁one ▁long ▁pat rol ▁during ▁the ▁entire ▁operation , ▁but ▁no ▁ships ▁s unk . ▁ ▁U - 5 9 ▁- ▁a ▁Type ▁II C ▁commanded ▁by ▁Har ald ▁J ür st , ▁which ▁s ank ▁one ▁Norwegian ▁vessel ▁on ▁ 6 ▁April . ▁ ▁U - Bo at ▁Group ▁Seven ▁Never ▁assemble d . ▁Group ▁Seven ▁was ▁designated ▁to ▁pat rol ▁the ▁Eastern ▁entrance ▁to ▁the ▁English ▁Channel , ▁but ▁was ▁cancel led . ▁ ▁U - Bo at ▁Group ▁E ight ▁Pat rol