A question about beating up-wind

[fredmiracle]

OK, so I get the tactical details of beating upwind--you go as close as you can to the wind in one direction, then tack and go as close to the wind in the other direction, thus overall moving you "forward" in a big zigzag. Since these ships can't get very close to the wind, it's a laborious process, because you do a lot of side motion for each small increment of forward motion.

My question is: what did this mean on a larger scale of voyages and campaigns?

1) For example, how long would the legs be? If a ship was trying to go somewhere that was "into the wind," how long would they sail on one tack before shifting? (or to put it another way, how often would they have to tack per day?)

2) Was this basically a straight-forward thing to do, or did it involve serious risks, wear & tear, crew fatigue, etc.?

3) I've read in books things like "well we were lucky the winds were against them, so they couldn't sortie while out squadron was dispersed" or something like that. If they could beat upwind, why couldn't they sortie? It doesn't seem to be a function only of very specific port configurations (although sometimes that seems to be the issue). So more generally--was this something a ship could do, but a fleet couldn't really? Or did ships/fleets only beat upwind for long periods under extraordinary circumstances? And if so, why? Because... it was so slow? you'd use up all your supplies? it was too risky?

Just trying to get a better handle on the strategic considerations captains and admirals faced...

[csadn]

1) For example, how long would the legs be?

This depends on how much room one has (more on this later), and how often one wished to risk a botched direction-change. Performing many short legs increased the risk of a screwup, but didn't require as much room; longer legs meant fewer chances of a botch, but required more room.

2) Was this basically a straight-forward thing to do, or did it involve serious risks, wear & tear, crew fatigue, etc.?

Again, it depended -- more direction-changes meant more work for the crew, which led to fatigue (and thence screwups) on both crew and parts; but a well-built ship could handle more work.

3) I've read in books things like "well we were lucky the winds were against them, so they couldn't sortie while out squadron was dispersed" or something like that. If they could beat upwind, why couldn't they sortie? It doesn't seem to be a function only of very specific port configurations (although sometimes that seems to be the issue). So more generally--was this something a ship could do, but a fleet couldn't really? Or did ships/fleets only beat upwind for long periods under extraordinary circumstances? And if so, why? Because... it was so slow? you'd use up all your supplies? it was too risky?

See above re room -- there's a "sideways" component to beating as well as forward movement; the further forward one moves, the further to the side one moves. Bays and harbors, being generally narrow and congested, put a cap on how far to the side one could move; so one either took the high-risk course of many short legs, or one waited until the wind was favorable.

By now the Actual Sailors are tearing their hair out over the complete lack of Technical Jargon, so I'll leave it at that. :)

[Craig]

To expand a bit: the sideways component that csadn refers to is leeway. The wind on a sailing ship is usually hitting it from the side. Because of this, the ship doesn't just move forwards, it also moves sideways towards the downwind side. When you're trying to make way upwind, this sideways drift is in the opposite direction of where you want to go.

In an unhandy ship (which can't point very steeply to the wind [1]) that makes a lot of leeway (determined by hull shape, wind strength, wind drag, currents, hull cleanliness, angle of lean, etc.), it's entirely possible for leeway to outweigh upwind progress to such an extent that upwind movement becomes impossible. This is a particular problem in a tight channel, because every time you tack you lose a lot of forward momentum and may end up drifting rapidly downwind until you regain it.

In bad weather (or just an unfortunate combination of tides and location) it's even possible for ships to be driven backwards and forced aground. Hence "the impervious horrors of a lee shore"...

--
Craig

[1] Modern folks tend to underestimate just how bad these ships were at sailing upwind. HMB Endeavour is the ship I'm most familiar with; in virtually any wind state, her upwind performance is more a matter of struggling to hold position rather than any amount of upwind progress. She struggles to point higher than about 75 degrees off the wind, and her leeway is such that any time you try to do that you actually end up travelling backwards at a substantial clip. Admittedly, Endeavour was a horrible sailer even by 18th C standards, but the warships weren't that much better.

[fredmiracle]

To expand a bit: ...

Thank you, that's very interesting.

It sounds like then, as a practical matter, if your orders told you to go to port X that is upwind from you, the best bet is just to wait for the winds to shift ('cause in the BEST case your progress will be agonizing slow, and worst case you'll be going backwards)?

[Craig]

Thank you, that's very interesting.

It sounds like then, as a practical matter, if your orders told you to go to port X that is upwind from you, the best bet is just to wait for the winds to shift ('cause in the BEST case your progress will be agonizing slow, and worst case you'll be going backwards)?

Depends on the ship and the situation; most decently built ships could make at least some upwind progress in most conditions. With a good ship and a lot of searoom (so you don't have to tack much), you could make acceptable upwind progress most of the time.

However, often what you'll want to do is slide sideways on the navigational scale, and shift your ship into bits of the ocean where the winds are known to tend to favour the direction you're after. This is why the trade winds were so important, and why the tendencies of local winds and currents is basic seamanship knowledge.

Often, the way to get to the city that's upwind of you is "stand 20 miles out to sea, where the winds and current are generally in the direction you're after, then angle back in to the target once you've worked past it".

--
Craig

[csadn]

I tried to avoid using Actual Naval Terms, as excessive jargon tends to obscure the description of what's going on.