Las Palmas to Rodney Bay: the 17-day crossing I'm planning around the calendar

I keep a short list of ocean legs I'm willing to plan the whole five years around. The Atlantic crossing from the Canaries to the Caribbean is the first one on it, and I've been rehearsing it on paper more than any other: roughly 2,700 nautical miles from Las Palmas to Rodney Bay, St. Lucia.

The arithmetic is simple. On the 50-foot cat we're researching, I'd budget 160 nautical miles a day under a reefed main and a poled-out genoa, which is deliberately conservative for a loaded boat with four kids aboard. That's about 17 days. Fast boats do it in 12 or 13, but those are crews carrying more sail than I'd ever want to be responsible for with a toddler asleep in the aft cabin. I'd rather plan for 17 and be pleasantly early.

The calendar is the real constraint. Hurricane season ends November 30, and the organized rallies leave in the last week of November for a reason: by then the Atlantic basin has mostly gone quiet and the trades have filled in. Leave a few weeks earlier and you're gambling on a late-season storm. Leave in January and you're fine on tropical risk, but the trades can be lighter and you spend more days motoring. So the window I'd aim at is the first half of December, with the boat provisioned and checked in Las Palmas by the middle of November.

The route question is rhumb line versus the traditional dogleg. The southern route drops toward the Cape Verdes before turning west, which adds miles but buys steadier wind and keeps you away from the lows that occasionally drop out of the north. The direct route saves a couple of days if the trades cooperate and punishes you if they don't. With children on board I lean south: more distance, less drama, and a reliable place to make a repair stop at Mindelo if something breaks in the first week.

My GRIB go/no-go criteria are written down, which matters more than the numbers themselves. Departure only if the five-day file shows no more than 25 knots sustained anywhere along the first 600 miles. Significant wave height under 3 metres, with swell period over 7 seconds, so the boat isn't being slapped sideways. No developing low within 500 miles of the track. I'll compare at least two models, GFS and ECMWF, and if they disagree about the same system by more than 5 knots I wait a day. Waiting a day costs almost nothing. Departing into a disagreement can cost a great deal more.

Underneath all of it is a financial adviser's habit: price the downside before you price the upside. The downside here isn't a bad forecast, it's a departure decision made because the flights for grandparents are booked or the rally has a party scheduled. I want the decision tied to the weather file and nothing else.

What I haven't settled is whether to do this crossing with an experienced third adult aboard. It would make the night watches far kinder, and it would cost me a berth and some privacy. I'm leaning yes for the first crossing, and I'll write up the reasoning when I've priced a few options. If you've done the Canaries leg with young children, I'd like to hear what you'd change.

The worksheet I'm using to compare boats against this kind of passage is at the worksheet page.