I'll bet you are thinking of
Shock Waves or maybe even
Zombie Lake
Here's the poster art to Shaock Waves:
Here's the description to Shock Waves:
This horror movie concerns a shipwrecked yachting party. Rose (Brooke Adams) and her fellow yacht-mates, including the captain (John Carradine) run aground on an island when they hit an odd-looking freighter. Once beached, they meet up with an aging SS Commander (Peter Cushing) who had been in charge of a crew of zombies.
