efforts of the powers that were to bury the story.

It has the makings of a good historical novel. Perhaps, it's a job for ... Captain America!

when the Japanese didnt think it could happen. However, by 1944 the Uboats could barely move in the Atlantic... anti sub air patrols, development of radar and sonar. Uboats couldnt even surface long enough to charge their batteries without being spotted (thus leading to "snorkles&quot , and their speed and range while submerged was very limited. The Uboats were essentially surface craft that submerged to attack, or they lay in wait for a target to come near. So, while it is possible for a Uboat to have crossed the Atlantic and attempted a rocket attack, it would have been against pretty long odds. My guess is military brass didnt want to give even a slim possibility any credence as it may have led to general panic.

is pretty much outside the realm of possibility. The largest U-boat was about 300' in length with a diameter of 30' while the V2 had a length of 45' and a diameter of over 5'. It would have been nearly impossible for a U-boat to launch a missle of that size. And the V2 reached a speed over Mach 4 so WW2 fighters would have been useless against it. USA Today is losing it over 1945's version of Sadam's WMD. A V1 was much smaller and slower, Allied fighters shot down several. They were not much of a terror weapon.

The largest U boats were the Type X B mine layers. Several were used to transport items to Japan. http://www.uboat.net/types/xb.htm

They had an overall length of about 278' and a beam of 28' 6" external but only 14' 8" internally.
It is conceivable these subs could transport either V-1s or V-2s. Launching would be an entirely different matter. The sub would have to surface, construct the missile then launch it. It would be extremely difficult.
Germany built 8 of these boats and all were accounted for with no gaps in their war records indicating such a secret mission.

The Type XIV supply boats would be another candidate. There is anecdotal evidence that one or two may have had trial ramps installed for launching V-1s but no conclusive proof of this.

By comparison, the purpose built Japanese I-400 class could carry and launch three seaplanes. They were 400 ft long and could launch all three planes in 45 minutes.
http://en.wikipedia.org/wiki/I-400_class_submarine