Y'all ever hear of boats down there?? Get the ol' rowboat out there with a fat guy with a pole in the bow to hold it down an' another not quite so fat guy in the stern with a saw with about a 48 inch bar. Stick the bar in the water if you have to, and whittle 'er down to size. Wear a raincoat, 'cause you're gonna get wet!
Wood, even oak, doesn't weigh anything underwater, and it'll float in smaller pieces. Every piece you cut off that's sticking out means another piece will come to the top. Git 'er done, and get lots of pictures while yer at it!
Sean