Sustained writing takes at least two kinds of energy, two acts of commitment, if you like. This week on the water You start with the tendril of an idea, a whisper of a story, something that, for reasons that are frequently inexplicable, excite your imagination. It doesn’t have to be much, but there’s something about it that beckons you, that says: “This is worth thinking about,” or, perhaps better, “This is something that generates a particular feeling in me that I want to explore, in a...