8 ▁tor ped o es , ▁with ▁the ▁exception ▁of ▁the ▁former ▁Deutschland , ▁which ▁was ▁fitted ▁with ▁six ▁tub es . ▁All ▁were ▁armed ▁with ▁two ▁ ▁SK ▁L / 4 5 ▁deck ▁guns , ▁and ▁carried ▁a ▁crew ▁of ▁ 5 6 . ▁They ▁had ▁a ▁cru ising ▁range ▁of ▁around ▁. ▁ ▁The ▁success ▁of ▁the ▁Type ▁U ▁ 1 5 1 ▁sub mar ines ▁led ▁to ▁" Project ▁ 4 6 ", ▁the ▁larger ▁Type ▁U ▁ 1 3 9 ▁" U - c ru is ers ", ▁designed ▁from ▁the ▁out set ▁as ▁military ▁sub mar ines . ▁ ▁Service ▁Deutschland ▁made ▁two ▁successful ▁commercial ▁voy ages ▁before ▁being ▁commission ed ▁into ▁the ▁Kaiser liche ▁Marine ▁on ▁February ▁ 1 7 , ▁ 1 9 1 7 ▁as ▁U - 1 5 5 . ▁ ▁Max ▁Valent iner ▁commanded ▁a ▁Type ▁U ▁ 1 5 1 ▁U - bo at , ▁, ▁and ▁under to ok ▁the ▁longest ▁cru ise ▁in ▁the ▁war ▁from ▁ 2 7 ▁November ▁ 1 9 1 7 ▁to ▁ 1 5 ▁April ▁ 1 9 1 8 , ▁a ▁total ▁of ▁ 1 3 9 ▁days . ▁High - sc oring ▁Wal dem ar ▁K oph am el ▁also ▁commanded ▁a ▁Type ▁U ▁ 1 5 1 ▁U - bo at , ▁ ▁in ▁late ▁summer ▁and ▁fall ▁of ▁ 1 9 1 7 . ▁ ▁List ▁of ▁Type ▁U ▁ 1 5 1 ▁sub mar ines ▁ ▁Seven ▁Type ▁U ▁