Originally devised for 2014’s Edinburgh Festival Fringe, The Diver is a one-woman show about Kate Plank, an explorer attempting her most challenging mission yet: walking from England to New York across the ocean’s floor. Using few props, a newspaper and some puppets, this show – somewhere between comedy, storytelling and empowering drama – attempts to immerse the audience in this aquatic experience.

It may have been intended, but the start of the show itself is slightly awkward, as the audience is not sure if it has started already. The play is presented as a mix between Helen Foster as an actress telling the story and Kate Plank, its main character. She leaps in and out of character throughout the show in a refreshing way, although sometimes these changes stop the course of the main story’s action. These interventions also serve as a way to interact with the audience and make them part of the action, creating a rather participatory press conference or even a kelp forest.

Even though the idea of the show is an interesting one, the resulting performance feels more like something that could have been great, but does not quite achieve it. The play’s underlying message is a beautiful one – believing in oneself, not living up to anyone’s expectations – but the way it is conveyed is irregular: sometimes bluntly self-empowering, sometimes bland and shallow. The script fails at delivering truly comic moments, but rather succeeds in keeping you smiling throughout. In this sense, it feels halfway there and undefined in its genre, even though the story keeps interest and delivers some beautiful scenes.

Helen Foster shows a great agility and a particularly good approach to physical theatre. However, her comic timing feels off-key at times, particularly at the beginning of the play. Maybe due to the script being irregular, some of the gags do not particularly work, even though Foster’s enthusiasm is certainly contagious. Her best moments come when she interacts with other ‘characters’, like the fish and the kraken. Using very simple puppetry – or none at all – she makes the characters alive and (very) likeable.

Despite having undergone some reworking after its Edinburgh run, The Diver needs still rewriting, particularly in its ‘comedy’ parts, in order to become the show it can be. However, Foster’s skill is beyond doubt, delivering some great moments and displaying an enthusiastic physicality that is both engaging and uplifting. It is, in short, an enjoyable play with some great moments and good ideas that can, and must, still be developed.

The Diver is playing at The Rag Factory until 2 August. For more information and tickets, see the Craft Theatre website.