It's a miracle the rocks don't rip through the bottom of the boat. The way it shakes, they're definitely hitting something, but the vessel holds and nothing splinters; Red will consider that a success.

He draws his sword, one hand still on the tiller, and watches the leviathan struggle in the shadows.

"Y'know, I'd love to. Mightily missing my rifle right about now. But that magic rock you've got seems to be doing the trick. I'm afraid I'll have to get much closer to do any damage with a blade."