The shark may be broken, but make no mistake about it, as Robert Shaw (played by his real-life son Ian) says to his fellow cast members Roy Scheider (Duncan Henderson) and Richard Dreyfuss (Liam Murray) after an uninspiring meal in a local seafood restaurant, “that shellfish will get you in the end, literally”.

And fear of extinction (personal and professional, climatic and nuclear) is the recurring theme which continually bubbles under the surface comedy of Ian Shaw and Joseph Nixon’s tight as a reef knot script directed with subtle precision by Guy Masterson.

Entering to the ominous strings of John Williams’ iconic score, the tetchy trio huddle round the table of the ill-fated Orca – the cabin fever-inducing design fittingly reminiscent of an old-fashioned snug – to chew the cud about art and religion, war and politics.

“There can never be a more immoral president than Nixon,” says the square of jaw and mind Brodie, drawing one of many prolonged bursts of laughter during one of many interminable delays in what is disparagingly referred to as the retarded offspring of Moby Dick and The Enemy of the People.

Each actor boasts that their character is the most important and in so doing compete against one another in a series of alcohol-fuelled games (board, card and mind) of one-upmanship. But as their insecurities and fears puncture their life jackets of bravado, it becomes clear that the mechanical artist affectionately known as Bruce, whose enormous frame dominates the poster and reduces their names to the bottom line of an eye exam, is the star.

An undeniable fact underscored with pin-dropping poignancy as Shaw recreates his father’s chilling monologue about the sinking of the USS Indianapolis whose doomed crew recoiled in horror as they were encircled by the “lifeless eyes” of imminent and eternal death.

Through a glass darkly, Robert Shaw slurs that it’s easier to make a good movie of a bad book. But what of a good play of a good movie? Well, the writers have triumphed where many have failed, as have the impressive cast who not only bear a striking resemblance to Messrs Shaw, Scheider and Dreyfuss in look, gesture and voice, but like the appreciative audience appear to be having a whale of a time in a show which is likely to make a big splash in Edinburgh and beyond.

Peter Callaghan