Episode 55 of "JAG"
s03e18 Tiger, Tiger

When Harm takes young Josh on a weekend cruise for Navy families aboard the frigate, pleasure turns to fear when the ship is taken over by terrorists who intend to fire missiles at Cuba. After Josh and Harm manage to elude the terrorists, they try to contact authorities about the situation. But the plan goes awry when Harm is found out, and he then tries to strike a deal with the terrorists while also racing to foil the plot before the innocent civilians get hurt.