Lots of fiction makes use of a ship being knocked off course by a storm as a way to separate and isolate the heroes; Ulysses, Crusoe, Gilligan. But just how far could storm knock a ship off course? I mean, these people were heading somewhere; Ithaca, Africa, and back to the traffic port.
I know there are a lot of variables to this sort of question, so maybe some historical examples could be illuminating. But let us speculate about a medium sized sailing ship, and 24 hours of a storm (you decide the storm’s intensity). When the storm was over how far off course are they?
It didn’t need a big storm, just a wind in an unexpectedly wrong direction. Square rigged ships could only sail within a few degrees of the wind direction, so a lot of the art of navigation was knowledge of prevailing winds.
As to how fa… That’s a piece of string question. As a maximum, we could multiply (say) 10 knots by 24 hours which might have them a full 280 miles in the wrong direction. Of course that would only happen if they kept sailing (running away from pirates?) without that, they would just run on enough canvas for steerage, so a small fraction of the above.
This is one of those “It depends” kind of situations. What form of navigation? What kind of ship? What is the material condition of the ship? How bad is the storm? How LONG is the storm? How much lee does the ship have before it runs agound? How long can it dewater before it founders?
When ships sailed from Europe to the Pacific, the standard route was via Cape Horn. It occasionally happened that storms in the southern ocean made the Horn basically impassable; ships would sometimes turn tail and run eastward, past the Cape of Good Hope and on to their destination.
Originally Posted by bob++ View Post
Square rigged ships could only sail within a few degrees of the wind direction …
For values of “few” that include “approximately 65”.
This seems to get confused a lot. Both posters might know exactly what they meant, but I’m not sure I do.
I’ve seen this was discussed in previous threadson this forum but here is a better link IMO, though focusing on square rigged warships of ca. 18th century which isn’t all ‘sailing ships’ ever.
Anyway the paper points out that the way this issue was discussed at the time can also confuse modern readers. Basically in theory square riggers of that time were supposed to be able to sail as close as 6 points off the wind. A point was 11.25 degrees, meaning by specific example that if the wind from coming directly from the north, 0 deg on the compass, the ship could steer a course of 67.5 deg, EastNorthEast, or 292.5 degs, WNW, but no further to northward than that. I assume that’s what Xema meant by around 65.
However the paper points out that in practice the capability was typically less, both in terms of the course, typically more the the east/west than ENE or WNW would be attainable on average against a wind from due N, falling short by a whole point wouldn’t be a lot. And also from the POV of the necessary assumption the ship would ‘tack’ back and forth between ENE and WNW to go due N on average. Those ships had limited tacking ability.
Sailing ships of earlier centuries had less capability, though fore-aft rigged ships, like the huge schooners of the twilight of large merchant sailing ships in the 20th century, could do better.
I don’t know how much of those stories was just romanticized stuff, but I do know that it was only relatively recently that ships could know both their latitude AND longitude, just from taking measurements on the ship at sea. It wasn’t until a reliable clock was developed in the late 18th century that a ship driven off course in a night storm could find out where it was without simply guessing to a large extent. Latitude can be deduced by measuring the position of the stars, but longitude requires knowing what time it is, relative to where you were when you left port.
Even before then, I suspect that a lost ship would start out being only a relatively few miles off course, but not knowing what course to set, would cause that distance to get worse the longer they sailed out of sight of recognizable land.
To expand on your post a little and add a couple illustrations…
I think there’s a misconception about what “degrees off the wind” means. It doesn’t mean a boat can only go directly downwind and left or right X degrees of that. It means they can go any direction except left and right X degrees of upwind. A lower number for “degrees off the wind” is better. It means you can get closer to sailing directly upwind (no boat can sail directly upwind).
Here is a square rigged ship’s points of sail drawn in 1794. The wind is from the southeast and it can sail any direction except where there’s not a little drawing of a boat. The area where it can’t sail appears to be about 67 degrees off the wind, meaning it can sail about 67 degrees left or right of upwind.
And while every modern boat is different, here is a similar generalized diagram for the modern era. The green area is where you can’t sail and it appears to be about 40 degrees left or right of upwind in this drawing. That’s a lot better than a square rigged ship but by no means was a square rigger being blown around whichever direction the wind wanted to blow it.
Not disagreeing with what you wrote (and I didn’t actually read the link because I’m lazy), but the simple solution to the poor tacking ability was to go the other way and jibe (they called it “wearing ship” back in the day). So if the wind was blowing from 0 degrees and they were headed, say, 080 and wanted to tack to 280, they’d simply turn starboard 200 degrees instead of turning port 160.
BUT, in a storm you wont run your full sails (in terms of area), and you put up only very strong heavy sails with little shape. So, as a result of reduction in wing shape and reduction in area, the sails ability is reduced while windage and weather helm (the force of the wind hitting the boat… ) increased… the ability to sail to the wind can reduce … past 90 off the wind… so that you can’t even go back … you MIGHT be reduced to 135-235 to the wind… downwind , if its a strong gale …
What any ship may do in a storm is to throw in a sea anchor, so that the boat is more strongly tied to ocean current rather than be blown by the wind…
The wind could blow you at 5 miles per hour. Currents may be that fast too. so the total COULD be 10 miles per hour , if the wind was blowing you down the direction of the current.
Which all goes to show how complicated 16th/17th century navigation was. Even with a good pair of chronometers the Master still needed to be able to see the sun at noon to get an accurate position. Dead reckoning was ok for a while; they cast a log to get speed through the water, and knew which way the ship was pointing, but there is nearly always a current to take into account and leeway has to be factored in. Byt the time they could get an accurate longitude, they could be hundreds of miles out.
Oh yes. I did understand that "a few degrees of the wind direction " meant either side of where the wind was coming from. Tacking into the wind would be impossible otherwise. From O’brian I get the impression that “wearing ship” was mostly done to save wear and tear on worn rigging, such as at the end of a long voyage or while blockading. Tacking is more efficient in terms of progress, but harder on the equipment.
Yes, I was just talking general sailing, not necessarily storm related. Running before the wind could also put you off course.
Tacking could also be tricky and required split second timing. There was a real danger that they couldn’t complete the tack before losing speed and finding themselves in irons. They had to have favourable conditions in which to build up momentum before even attempting it.
Cabral, considered the first European to “discover” Brazil, was trying to get around Africa.
So, that’s about a two-thousand-mile detour caused by a storm and/or unfavorable winds.
A true sailing ship was a vessel with 3+ square-rigged masts. Vessels of this size never used sea anchors.
They would occasionally heave-to, and ride out a storm with minimal sails - typically, just enough to make the ship want to keep its head in the desired direction relative to the wind.
Not to fight the hypothetical, but apparently Ulysses got caught up in a nine days storm. But considering he only had a 650 mile sail in front of him and it took him ten years, when you’re averaging 65 miles/year, a couple of hundred miles is a big deal
As an aside, trying to Google the distance from Troy to Ithaca is a nightmare because the Internet insists on telling you that it’s a three hour drive from Troy, NY to Ithaca.
I guess you could call it unfavorable winds, but he was never off course. He sailed west to avoid the doldrums, he just happened to run into Brazil before he turned south.
Going backwards was acutely embarrassing.
