Salute! and Welcome aboard OKH!
Go here
http://www.mpgtext.net/u-boot/ for your complete, one-stop "U-Boat War-Mart" to find almost ANY available mod (including no-fatigue mod)
A gentleman by the name of Terrapin runs the site. Downloads are FREE.
However, it is currently undergoing periodic maintenance and will be back up sometime tomorrow.
Prost! and Happy Hunting!