Ah, another WWII idea. There was the "Disney bomb", a rocket assisted munition designed, iirc, for the U-boat pens.
Accuracy being what it was in those days...it wasn't all that big of a success.
Barnes Wallis
Genius!
“Grand Slam bomb”
http://www.youtube.com/watch?v=R-Mm-zFW_nA
http://en.wikipedia.org/wiki/Earthquake_bomb