I really tried write like a pirate for the opening of this post, but I started sounding like Snoop Dogg. I'd start with "yarrs" but end up adding "-izzle" to the end of words. It got surreal. So instead of being incredibly clever, I'm just going to give it to you straight: this is a Minecraft map where two battleships set to each other across the briny deep, using those complicated bits of Redstone machinery that I never understand to fire TNT across the briny sea. Er, yarr? The ships are anchored opposite each other, and in a hilarious disregard for human safety they fire blocks of TNT using other blocks of TNT loaded into the cannons. Video below, fo' shizzle.
The cinematic trailer below shows the fun you can have on a multiplayer server with the nautical nonsense, a battleship teeming with TNT tossers aiming and firing. What it doesn't show is how to get that wonderful water, which I believe is this water shader. Everytime I've used that I end up with a black screen, so I hope it works for you.
There's a more descriptive video, showing how to load, aim and fire, as well as some background as to how the damn cannons work. Redstone is still basically magic to me, which would make these guys wizard pirates. Think about that.