▁References ▁ ▁External ▁links ▁ ▁Occ ident al ▁Park ▁ ▁Category : P arks ▁in ▁Seattle ▁Category : S qu ares ▁in ▁Seattle ▁Category : P ione er ▁Square , ▁Seattle <0x0A> </s> ▁Type ▁U ▁ 1 5 1 ▁U - bo ats ▁were ▁a ▁class ▁of ▁large , ▁long - range ▁sub mar ines ▁initially ▁constructed ▁during ▁World ▁War ▁I ▁to ▁be ▁merchant ▁sub mar ines ▁and ▁later ▁used ▁by ▁the ▁Kaiser liche ▁Marine ▁( Im per ial ▁German ▁Navy ). ▁ ▁Background ▁In ▁addition ▁to ▁the ▁cargo - car ry ing ▁sub mar ines ▁ ▁and ▁ ▁( lost ▁on ▁a ▁cargo ▁voyage ▁in ▁ 1 9 1 6 ▁while ▁it ▁was ▁still ▁a ▁merchant ▁sub marine ), ▁six ▁further ▁large ▁cargo ▁sub mar ines ▁were ▁ordered , ▁originally ▁designed ▁to ▁ship ▁material ▁to ▁and ▁from ▁locations ▁otherwise ▁denied ▁German ▁surface ▁ships , ▁such ▁as ▁the ▁United ▁States . ▁ ▁On ▁ 1 6 ▁December ▁ 1 9 1 6 , ▁four ▁under ▁construction ▁in ▁the ▁Re i her st ieg ▁and ▁Fl ens burger ▁Schiff bau ▁yards ▁were ▁taken ▁over ▁by ▁the ▁n avy ▁and ▁converted ▁to ▁military ▁specification ▁as ▁Type ▁U ▁ 1 5 1 ▁U - bo ats , ▁being ▁designated ▁ ▁to ▁. ▁The ▁remaining ▁two , ▁along ▁with ▁Deutschland , ▁which ▁became ▁, ▁passed ▁into ▁naval ▁control ▁in ▁February ▁ 1 9 1 7 , ▁as ▁ ▁and ▁. ▁ ▁All ▁were ▁fitted ▁with ▁two ▁bow ▁tor ped o ▁tub es ▁and ▁could ▁carry ▁ 1