What is the author's tone in Kon-Tiki: Across the Pacific by Raft by Thor Heyerdahl?

Thor keeps inter-human drama to a minimum. Squabbles may have broken out on the raft or during the frustrations while arranging for the voyage, but he chooses to discount these incidents if indeed they happened. Everybody moves ahead with the assumption that success is not only possible, but also inevitable.

Internal conflicts do come out, mostly in Thor. He has his periods of doubt and fear, as would be expected from any person out on a raft in the middle of the ocean. Yet he has also carefully considered the mixture of personalities with whom he spends over three months on the ocean. Knut the joker, Bengt the scholar, Erik the artist, Torstein the technician and Herman the scientist blend well with Thor the dreamer. That no two individuals are alike is an important characteristic of the crew because conflict often arises from two people being too much alike. As such, the crewmembers deal with their own feelings by either keeping them hidden or acting them out in harmonious ways.

Thor characterizes the ocean as being the main threat to wellbeing. High seas make the start of the voyage a major problem, but this tension soon releases with calm weather and a steady movement toward their goal. Thor paces the tension and release, which probably reflects the reality of ocean travel. Major life-threatening tension starts and ends the journey, with lesser problems sandwiched between. The use of mystery regarding some of the sea creatures encountered keeps the story moving, along with sharp observations and a few humorous incidents.

Thor's tone changes from the observant to the breathless, depending on how close to annihilation the crew approaches. He narrates the story as if telling it to a friendly audience in an intimate setting, a good style for any memoir and a very effective one for a true-life adventure.