Quote - ...On the side of Blackbeard, while I me self do not believe in the story of his body swiming around the ship, but to take from the accepted facts surrounding his death and use them to lend support to Klaus Störtebecker's; how did Blackbeard manage to continue to fight with so many pistol shots and sword wounds? Why did he not fall long before he actually did?
Again, most likely (as expalined by the 'hard cores' and 'scientists') due to strong rum and opium. (remember, liquer back then was even more strong then the strongest brewed today, and NO country had 'regulations' as to how strong it could be. Read up on how Rum got it's name)...

By all accounts, Blackbeard wasn't a small man.  While some accounts could be simple exaggeration, it's likely he was a large man for his day.  The bigger you are, the harder it is to get to your vitals.

As far as bodies walking without heads - It's "possible."  However, there would be no motor control to speak of, no mechanism to communicate "balance" and certainly not much in the way of coordinated effort of motion in a single direction.  Movement would be dictated by "shock" firings of muscles and, perhaps, some specialized areas in the spine that some have suggested act as relay centers.  (something I read not too long ago but can't find a link on atm)  I suppose something like that could be shortcircuited by a beheading and fire off in some sort of chain reaction that would mimic movement.  But, as far as standing up?  No, that is so unlikely as to be practically considered as impossible.  While the inner ear does provide the majority of our sense of balance, muscle resistance also helps.  Yet, there is nothing below the neck that I know of that can interpret that resistance and make sense of it.  A fish flopping on the deck would have more of a chance of establishing itself as being "ambulatory" than a headless corpse.

Then... there's the true story of Mike the Headless Chicken. :)  If you haven't heard of him before, take a look, amazing stuff!  http://www.miketheheadlesschicken.org/index.php