Thanks rconch, aktungbby, mittelwaechter and all for the informations and links. It is interesting to know that were also made War games, as in the quote "In the Autumn of 1936 war game of the Naval Academy Exercised the successful engagement of U-Boats against French troop transports in the Mediterranean, Allowing after 6 weeks to re- deploy the U-Boats to the North Sea to unite with the remaining fleet to deny France blockading the North Sea. "
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Visits to foreign ports as (Iceland, Finland, Spanish etc) before the war, as in the quote " The U-Flottila "Weddigen" with several boats visited Helsinki, Finland from 06th to the 12th of August 1937, accompanied by its support tender ‘Saar’".
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"Port calls in foreign countries. The new U-Boats of the Kriegsmarine carried in October Several visits to foreign ports During Their training and exercise journeys. The mentioned above, U-Boats participating in the operations embargo During the Civil War did Spanish Also call at ports other than Spanish, such as Lisbon or Tangier. "
http://dubm.de/lang1/kriegsmarine_u-boats-1.html
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“Herzog mentions a number of 12 further U-Boats after "U-33" and "U-34" sent to the sea areas before Spain”
http://dubm.de/lang1/the_spanish_civil_war.html