It was a frigid December night in the Arctic Sea. Aboard the Scharnhorst, the forecast of harsh weather had everyone on edge.

After nearly three decades out of service, this Soviet-era, nuclear-powered behemoth is set to plow the waves once again.

President Trump’s announcement of a new “Trump-class” battleship, the largest U.S. surface combatant since World War II, promises a floating arsenal of hypersonic missiles, railguns, and ...