Motorsailing in the gulf stream
currently in: the gulf stream
latitude 25°41.178N, longitude 79°34.509W at 1430 EST Feb
9th
At the moment we are motorsailing southeast at about 5.8 knots, in light wind that's just north of east (or so it seems by our dubious instrumentation); we're headed quite a bit south of our target, but the current is sweeping us somewhat to the north, and we're hoping that either the current will become more powerful, or that the wind will execute its promised southerly shift soon and we'll be able to motorsail on the opposite tack.
Motorsailing - motoring with our mainsail up - may seem like a compromise, but it's a smart compromise. We can point much more directly into the wind and make more speed than sailing would allow us to. We can't go as close to the wind as we could without a sail, but it's faster and far more comfortable this way, as the sail keeps us slightly heeled and we slice through the waves rather than wallowing this way and that.
Quite a few boats left earlier than we did. Many of them turned around, citing too-big seas, uncomfortable conditions that slowed them so much that they didn't think they'd make their destinations in time. We suspect that some of them left too early - the wind speed was still dropping, and the wind shifting east from north, during the morning, and conditions in the gulf stream were probably worse earlier. But we also saw one boat turn around only a mile in front of us, when we were about five miles from Miami. On the radio we heard them say that it was too choppy, they couldn't make any speed and they were too comfortable. We'd seen that they didn't have a sail up; maybe if they had, and had fallen off a bit so that they could motorsail, they would have weathered the conditions with more ease. The seas are barely 2 feet, and it's really not bad at all with a little sail up.
The thing is, for a sailor, the fastest (or most comfortable) course may not necessarily be a straight line. It's not really intuitive, but if you fool around with a little vector math - just drawing lines on a chart - you can see the effects of working both with and against the current and wind. If you can make 6 knots a little off the wind, but only 4.5 knots going straight into it, taking the longer course may only cost a short time - and it may actually be faster. And when you factor in the comfort level, it's hard to justify bashing yourself and your equipment. This is especially true on longer passages, because wind and sea conditions are likely to change during the passage. In particular, when you're crossing the gulf stream, which rockets north, it makes sense to head a little south before you hit it, then allow it to take you a little too far north when you're in the thick of it, then correct your course on the other side, when you don't have to fight it. This is the "S-curve" shown on the charts and in the guidebooks, and it really does work.
Oh! I just felt us "tack" - Britt noticed the wind coming around a little more to the east, so he changed course so that our main would fill from the right rather than the left. Now we're going with, rather than against, the current: we're making 7 knots on a course of 071° - and because we'd been steering "too far south" before, we're almost right on course for North Rock, which bears 072°. We've still got 21 miles to the mark, so even if we end up too far north, by the time we get closer the wind should have shifted more southerly, and we should be out of the main current, and it should be easy to make a bit more easting.
Of course, North Rock only marks the end of the first leg. It looks as though we'll get there late in the afternoon, which will be great, although we're not worried about getting there after dark as we have both radar and computer navigation. Then we've got another 75 miles to go to Chub Cay, and if the weather and daylight hold out tomorrow we may push on the 35 further to Nassau.


