While it has already been said that the Kreigsmarine were the least political,It should be noted that Doenitz himself was a fervent fan of Hitler,even when he failed to deliver all that he promised and Unkle karl would go to see him and swear that he was going to give him a piece of his mind,but as soon as the meeting was over he would come out glassy eyed and hypnotised by Hitler's mixture of browbeating and cajoling(an affect he had on many

)Also let us not forget that when Hitler did the decent thing and went bang,who did he pass the poison chalice to?,someone who would uphold his twisted ideology and ideas,Karl Doenitz!Who even at that late stage of the war still thought a truce with the western powers was on and that a war could be continued with the russians,and all that entailed

So while it is right to suggest that those in the boats were apolitical and thought Hitler a joke with a funny charlie chaplin tache,there were those at Bdu who were fervent nazis.Oh and welcome aboard,sink'em all