Kids love pirates. Kids also love dinosaurs. So author Giles Andreae and illustrator Russell Ayto struck gold with their picturebook series Captain Flinn and the Pirate Dinosaurs. Theatre company Les Petits adapted the first book in 2013 and have turned one of its sequels into a musical for the over-threes with a couple of roof-raising, timber-shivering tunes, poop-deck gags and puppetry that’s packed with personality.

It’s framed as a school play rehearsal gone wrong and Zoe Squire’s set features a charming, if not quite seaworthy, ship made from assembly-hall benches, a stepladder and a trampoline. Our three heroes – Flinn, Pearl and Tom – are insufficiently individualised for us to really root for them. Much more appealing are the dino-pirates (played by the same actors, Ellie Pawsey, Tom Myles and Stephan Boyce) and the diabolical Captain T-Rex (Mark Middleton, doubling as the highly strung Miss Pie).

Puppet designer Max Humphries and costume-maker Zahra Mansouri have dreamed up some delightful dinosaurs, including a delicate diplodocus and a tyrannosaurus made from oven mitts and a broom. There is a mix of rod, string and shadow puppetry, plus a towering T rex.

Much more could be made of an interlude when the gang forget the cutlass and instead cut loose at DJ Rocktopus’s underwater disco, complete with DayGlo rave jellyfish. The plot is blown a bit off course and some quieter moments among the blizzard of clever and corny jokes would be welcome. While no piratical pun is left un-plundered, these heroes never quite steal our hearts.

• At the Pleasance Courtyard, Edinburgh, until 19 August.