Here is where my being argumentative has a positive side: I was hoping someone would prove me wrong and tell me how to defeat larger attackers in the water. No Navy Seals logged in? hahaha
I will reverse Mr. Stephens statement and say that what we think of as 'aikido' may not work for very small person against large, but I believe there is almost always a way for a small person to defeat a larger in the real world.
Excuse me now, I have to say my 10 'hail Mifune's' before I go to work.