Knd of captures the mood.
I'm reading this at the moment. Kind of sets the perspective whilst occasionally making uboats out to be weapons of mass destruction.
Its reduced on kindle at the moment too.
http://www.amazon.co.uk/dp/B00E8HPMY...2Fshoshop.html
Link looks bust. Its called 'twighlight of the u-boats' and its a clever title since that's when they attacked too