After that – nothing. Six unbroken days of Atlantic, stretching all the way to the horizon and our restless imaginations.

On a voyage with this many sea days in a row, time aboard ship, I discovered, has the quality of a sojourn with Homer’s lotus-eaters. It slips by unmeasured. Three days, four days slide like water under the hull. I’d wake most mornings for yoga on the aft deck, though “wake” suggests more intention than I possessed. Really, I’d simply find myself there, half-conscious, while the instructor murmured something about setting intentions and the horizon bled from charcoal to apricot.

One day, we crossed the Tropic of Cancer and sailed officially into tropical waters. And heat. Explora I’s four pools – the wake-edge infinity of the Astern, the sun-lit Conservatory with its retractable glass roof, the adults-only Helios, the hidden Atoll – claimed their brigades of determined sun-seekers.