Col John Blashford-Snell, and the book about him crossing the Darien Gap. At one point the expedition was trying to cross a river. Some of the crew had made it but Blashford- Snell was still on the previous bank yelling out across the water asking about how they did it. One of the crew called out back to him: "put your bloody pith helmet in the water and float across in that"!
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