Koh Yao Noi floats in the sultry blue of Thailand’s southern Andaman Sea, a quiet little island with some great rock climbing. We caught the regular ferry over from the mainland, which is an oversized wooden long-tail laden with locals and their goods (notably, an enormous bag of raw chicken wings). It takes about an hour and is a really beautiful ride. Hundreds of island rise steeply out of the water in this area – limestone monoliths topped with abundant shaggy jungle. Many of the cliff faces are cut in at their base by the sea – from a distance (particularly at low tide) they look like so many marbles rolled carelessly into a clear, still, puddle. Compared to neighbouring islands like Phi Phi,…