This low-budget horror movie very much benefits from the typically excellent craftsmanship expended even on such low-end efforts by major studios in Japan at the time. I can't concur with others that it reminded me at all of "The Fog," apart from liekwise involving ghostly vengeance for death at sea. The script is a bit confused, particularly once we get towards the end, when in addition to the supernatural element it turns out there's a sort of mad-scientist thing going on--making for a narrative agenda rather sillier and more overloaded than this movie can pull off.
Still, that doesn't matter so much, because the atmospherics are very effective in their widescreen B&W handsomeness, despite the fairly cheap FX. (Particularly the kind of tank miniatures more familiar from Godzilla-type films, with "stormy seas" clearly not much more than bathtub splashing in slo-mo.) The performances are decent enough, and while the story isn't terribly scary, there's a nice mood of creeping dread--you can almost feel the ocean air permeating inland, bringing ghosts and violent death with it.
