I have written in the past about how the announcement of James Cameron’s The Abyss triggered a mad rush of competing film projects, each intended to profit from audience expectations by getting their own cheaper undersea thrillers into theatres first. Of the various knockoffs, George P. Cosmatos’ Leviathan (1989) was probably the most successful in terms of revenue and creativity. The worst was almost certainly Juan Piquer Simón’s The Rift (1990). Somewhere in between sits Sean S. Cunningham’s Deepstar Six. It works functionally, if rather stiffly, and while it is never going to be confused for quality cinema it does hold a certain B-grade appeal.

The film focuses on a crew of 11 pilots and scientists working out the last week of their tour on the undersea military base Deepstar Six. When one scientist discovers an unexplored cavern, their superior orders for it to be collapsed with explosive charges – lest it delay an important nuclear storage project. When the resulting explosion frees a mysterious ocean-borne predator, a series of mishaps put the lives of the entire crew at risk.

There is a utilitarian sense of Cunningham’s direction here. His film favours plot over style, and does an efficient job of introducing its characters, throwing them into crisis, and then watching them fight to survive against an enormous scorpion-like menace. Ridley Scott and James Cameron’s Alien films seem like a major influence, although Cunningham lacks any of the design flourishes or inventive stagings that made those films so remarkable. It must be said there is not much Cunningham does wrong here, but at the same time there is little or nothing that stands out. This is a simple story, simply told. Watchable but unmemorable.

The cast generally acquit themselves well, and comprise a combination of servicable unknowns and industry veterans. Miguel Ferrer is a stand-out, as is Hill Streets Blues alum Taurean Blacque. There is an unexpected nod to gender balance too, with Nia Peeples, Nancy Everhard, and Cindy Pickett all playing key leading roles.

It is all surprisingly restrained as well. In a film running 90-odd minutes, the monster does not actually reveal itself until the one-hour mark. Even then it is well-realised and shot in a manner that enhances its appearance rather than show off its shortcomings. While it is true that the film wobbles during a rushed climax, it still manages to wrap things up without ever seriously embarrassing itself.

With a film like this, expectations are key. Deepstar Six pretty much does what it sets out to do. There is tension and thrills, and a cast of panicky characters getting killed off one by one. There is nothing done here that is not done better in other films. B-cinema serves a purpose, however, and Deepstar Six serves it well. It is watchable. It is occasionally surprising. At its worst it can be laughed at. It is an important part of the entire 1989 Abyss phenomenon.