Yes I know this is an older thread, but I think I can add a silly observation to this discussion of 'skip bombing'. And I like to contribute when I can. Anyway - it works on glass smooth water - like a lake. I don't think it's going to work too good against the ocean surface ruffled by the wind / tides etc. Probably why they kept trying to use torpedoes for the job.
This idea reminds me of that scene in Saving Private Ryan, where they pull the pins on the mortar rounds, slam them down - then throw them. Who was the first one to try that? Pulling the pin and then slamming the live round against the ground I mean.
While doing the skip-bombing thing - the Brits practiced with specialized equipment against a dam. It's the 'flying over the target' that would give me pause.
"Sure Gus, you skip bomb that destroyer. I'll be over here seeing how much abuse a live mortar round can take before it explodes."