Sub is a slang word for submarine;
U-boat is a designation for a German Sub;
S-boat is a designation for a type of Am Sub; P is another as well as
many other letter designation, BUT NO U designation, that is a
designation for a German Sub

If you don't want to accept that, so be it. Be happy in your ignorance
and your creators Junk business

Ole Thom
P/S give Susy my regards