Mosasaurus could reach up to 17 meters length. For reference, that is the average length of sperm whales.
If we look at sperm whales, there are accounts of 26 meters sperm whales sinking 19th century whaling ships.
The whale rammed Essex, rocking her from side to side, and then dived under her, surfacing close on the ship's starboard side. As its head lay alongside the bow and the tail by the stern, it was motionless and appeared to be stunned. Chase prepared to harpoon it from the deck when he realized that its tail was only inches from the rudder, which the whale could easily destroy if provoked by an attempt to kill it. Fearing to leave the ship stuck thousands of miles from land with no way to steer it, Chase hesitated. The whale recovered, swam several hundred yards forward of the ship, and turned to face the ship's bow. The whale crushed the bow, driving the vessel backward, and then finally disengaged its head from the shattered timbers and swam off, never to be seen again, leaving Essex quickly going down by the bow.
Now, considering that middle age ships were less robust than 19th century ships, and that your creature is larger than a Mosasaurus, it's possible that the task can be completed.