get a bucket or large mug / cup, and start bailing out the boat.
if you try and lift it with tractor, you are just asking to damage something.
if it was on the lake here on the farm. i generally can just drag the boat up onto the bank, let water spill out, and keep pulling it up on the bank higher and higher. till i get rear end up of boat up on solid ground. and then still may have to get a cup to dump water out with a mug / cup before getting a couple folks to flip it over to remove the final bit of water.
but to try and flip the boat that is seating already on the ground, that is full of water. is asking for trouble and most likely the boat will not make it through. water weighs much much more than what you might think what is it like 7 lbs per gallon. to figure out how many gallons length x width x depth (all in feet) x 7.48 = gallons. i am guessing right now full of water boat weights over 2,000 lbs and 2,000 lbs is just the water.