Now playing at London’s Ambassadors Theatre, The Shark is Broken finds the cast of Jaws (Roy Scheider, Robert Shaw and Richard Dreyfuss) stuck on a boat while the notoriously defective prop shark is being an open water diva.

The similarly named men squabble, scuffle and sozzle between shooting the chondrichthyan classic, which defied the odds (faulty mechanics, bad weather and Shaw’s drinking) to become the world’s highest-grossing movie for all of two years, before Star Wars blew it out of the water. Nicely staged on an open cross-section of the vessel against a constantly moving ocean background, The Shark is Broken breaks down how the trio passed the time in a cramped cabin, and does so with a boatload of charm and affection for its characters (or is it its actors?).

Shaw is played by his son Ian, who also co-wrote the script, giving the piece a cathartic quality – although if you go expecting the rawness of Shia LaBeouf’s Honey Boy you will be left hungry. This has nothing like as much depth, skimming the surface of several topics (the state of the film industry, the acting profession and of course Jaws itself) without settling on anything for long enough to properly sink its teeth into a theme. The focus is on the less-than-chummy relationship between the salty Shaw and freshfaced Dreyfuss (Liam Murray Scott), a dynamic that rather leaves Scheider (an uncanny Demetri Goritsas) at sea.

Sadly the play never quite decides what it is: behind-the-scenes insight or comedy skit. The constant jokes about the present are either nonsensical or just tiresome; a couple of winking references (“This will never be a hit!”) are inevitable but having the 1974 characters predict the current use of virtual actors is illogical, and by the tenth iteration of the same gag you will be reaching for the lifejackets. Despite a great premise, the show’s Fringe origins are too often apparent. It was probably a watertight hour but stretched to 90 minutes? You’re gonna need a better script.