Nautilus can break through a ship’s hull

The impact shook the ship again.
Not good, said Zzzap.
Hussein ran for the railing. “Is he attacking us?”
“He might’ve already broken through the hull,” said Eliza. “He’s strong enough.”

Excerpt From Ex-Isle, pg 528
Peter Clines
https://books.apple.com/us/book/ex-isle/id989619017