Ship Ahoy, a patriotic musical comedy of the WWII era, swings to the tempo of its big-band times. Eleanor Powell plays a leggy lead dancer on a cruise ship who is asked to transport a mine to Puerto Rico. Neither she nor her pulp-fiction-author beau (Red Skelton) knows she's actually working for spies --who got the idea from one of his potboiler novels! The supporting cast includes Bert Lahr (the Cowardly Lion in The Wizard of Oz) and V