Not as exciting as the box cover artwork might suggest, with a painfully stilted characterisation by Ben Gazzara and capable supporting cast trapped in one-dimensional roles. The story concerns militant, officious salvage expert (Gazzara) contracted by an aquatic research team to recover a stricken underwater manned probe that has descended into a deep sea ravine. Gazzara makes it clear from the outset that his goal is only to locate the vessel for insurance purposes, except Mimieux’s companion is one of those aboard and she ups the ante in spite of escalating challenges.

Pidgeon and Borgnine have little opportunity to establish any characterisation, while Mimieux simply frets and affects anxiety to demonstrate her ‘depth’ of character. The friction between her and Gazzara is about the only palpable action in the whole picture. The special effects consist of intense magnification of gold fish and other aquarium species, while endless jolts and turbulence puts you in the environmental context. As far as dialogue goes, the technical spec consists mainly of references to rudder malfunction and oxygen saturation. Riveting stuff.

Disappointingly, the film ends abruptly where it could have developed a more convincing, compelling climax. After waiting 95 minutes, the audience is treated to a Jules Verne moment in which ‘giant’ eels corral the probe’s survivors as they run out of oxygen. But just as the action gains momentum, the film ends. Five more minutes of that encounter might have earned another star, but this underwater adventure is mostly talk and no action.