Kon-Tiki is a dramatisation of Thor Heyerdahl’s 4,300-mile, 101-day journey across the Pacific by balsa-wood raft, which took place in 1947, and was a remarkable achievement, unlike this film, which so isn’t. True, it does what it says on the tin. There’s an ocean, and it’s traversed. There is jeopardy, most notably in the form of a big plasticky shark.