Mystery Liner (1934)

Professor Grimson (Ralph Lewis) invents a device which can power a liner by remote control. Enemy spies send an agent to mix among the various vacationers unnoticed to sabotage the ship. The inventor is strangled and the crew must wait until the steering experiment is proven a success before the saboteur strikes. Also Captain Holling (Noah Beery) takes ill right before the ship is to depart. Also stars Astrid Allwyn and Edwin Maxwell.