 As a UB II boat, "U-45" could also carry twice the torpedo load of her UB I counterparts, and nearly ten times as much fuel.To contain all of these changes the hull was larger, and the surface and submerged displacement was more than double that of the UB I boats.The German Imperial Navy ordered "UB-45" from AG Weser on 31 July 1915 as one of a series of six UB II boats (numbered from to ).