That hole wasn't made by any torpedo or collsion unless it was a collision with a saw blade. That hole is almost perfectly round, no metal pointing inward or outward, no jagged adges, it's just a perfect clean cut. Last I checked, there wasn't a torpedo equipped with a boring bit to cut into a ship. And if it had been melted, it would still be rough edged, and there would have been corrosion from the action of the salt water on the hot metal.