As already mentioned, unload the boat. If you have a stuck anything, especially if it is supposed to float, unload it. Would that ship float out of the predicament if it were unloaded?
We should be seeing that instead of digging into the side of a canal with who knows what consequences to the integrity of the canal side. Maybe dredging around front section of the bow.
But really, just unload the thing. Less weight = more buoyancy, right? What's to expose if you do?