Shanghaied - Carey Fessler

Shanghaied: forced to join a ship lacking a full crew by kidnapping or other underhanded means.

Twelve-year-olds Emma and Scott stumble across a dark secret and are shanghaied by a rogue submarine that once suffered a ghastly fate: a radioactive incident that transformed its crew into mutants.

They are plunged into the depths of the ocean, far beyond the reach of help, where the Blackwolf battles against lurking enemy navies.

Now they must find a way off the submarine without being killed first—or even worse, being forced into service for the rest of their lives.

The race to escape has begun.