[pickinthebanjo]

Engineering in the Royal Navy - http://www.hnsa.org/doc/pdf/engmag.pdf

U.S. Sonar operators Manual - http://www.hnsa.org/doc/fleetsub/sonar/index.htm

Ship camouflage Instructions - http://www.hnsa.org/doc/camo/index.htm

Anatomy of a VII - http://www.scribd.com/doc/23575323/A...ype-Vii-U-Boat

U.S. 21-Inch Submerged Torpedo Tubes - http://www.hnsa.org/doc/fleetsub/tubes/index.htm

U.S. Submarine Periscope Manual - http://www.hnsa.org/doc/fleetsub/pscope/index.htm

Main Propulsion Diesels - http://www.hnsa.org/doc/fleetsub/diesel/index.htm

German Optics - http://forum.sukhoi.ru/attachment.ph...2&d=1255798351