How did 18th and 19th Century warships find each other in open ocean?

So was it actually common for ships to run into each other and start shooting in the open ocean? It seems like pretty long odds even if you knew where an enemy ship was heading to. The ocean is a big place, and visual contact is all you have. I can see catching up to an enemy in or near port, but otherwise it would venture it would be unliekly, even if the two ships were looking for each other. If one was trying to avoid being found, it must have been even harder.

Watching Master and Commander a while back, it seems like the French and English ships met three or four times in two oceans over the course of a month or two. Did similar encounters ever really happen?

As big as the ocean is, ships of the time were usually found in known shipping routes or near ports, rivers, capes, or other transit points. If you were patient, it wasn’t that hard to get yourself into a world of hurt; you just had to know where the enemy would likely pass by, and that wasn’t too hard to figure out most of the time.

Actually catching an enemy ship in the middle of the ocean away from a shipping route was very rare indeed. That was still a pretty tough thing to do as late as the twentieth century; even in WWII it wasn’t that easy to catch an enemy ship in open water if it wanted to avoid being found.

Keep in mind that prior to steam power, all of the ships would have been using the same winds/currents so the scope of the search would have been greatly reduced, especially if you knew where they were going. Likely you’d be on pretty much the same route and using the same winds.

“…I wonder if he is using the same wind we are using…”

My klnowledge of this comes from reading books, especially C.S. Forester’s Hornblower novels. So be warned

1.) You can actually see ships that are prettyy far away, especially if you’re on top of a mast with a telescope.

2.) Sometimes you know enough to help you locate a ship. In one book (God, I used to know these back to front at one time. I think it was Hornblower and the Atropos) they describe exactly how they searched for an incoming Spanish fleet – they knew the port the ships would be coming in to, and reasoned that after crossing the ocean they wouldn’t be sure about their position, so they’d come in along the correct longitude (easy to determine from shooting the angle of the pole star). So all the searching ships did was to spread out in a north-south line as far from each other as possible while remaining in sight of each other, with the center ship right on the longitude they expected the ships to be moving along. This worked.

3.) Ships did just blunder intio each other. They also managed to just miss being seen. A good captain could maximize his chances of seeing enemy ships, using whatever information he had, and to do his best not to be seen when that was required. Sometimes, though, you wanted to be found.

4.) Sometimes ships from opposing fleets wanted to be found by each other, and made every effort in this direction. When you’re trying to achieve dominance in some arena, and think you’re a match for your opponent, there’s no point in hiding.

Nitpick - that would be latitude, from shooting the Pole Star or, more usually, the Sun. (Estimate when midday is and start taking shots with your sextant. The angle peaks at local noon and then begins declining. Midday sun angle varies not only with the latitude but with the day of the year, but the latter variable is what almanacs are for.) Longitude was harder to find and relied on an accurate chronometer to compare the local noon time just found with the clock noon (set to the time at zero longitude before leaving port).

Navigating by latitude-and-hope was also known as “running the westing down”, that is, you got the right distance South good and early, and then headed West until you made landfall.

“Inconceivable!!” :smiley:
(And Malacandra stole my nitpick about latitude and longitude :wink: )

Don’t forget Spies.

Major Naval operations took weeks/months to prepare. Every major port had a few spies, for this & that country. Eventually, they’d buy enough drinks for a talkative Junior Officer, & then dispatch a message Home—long before the Fleet up-anchored. Probable course would be easy to guess. And intercept.

Well, there were populated shipping lanes (wooden ships had to travel with the prevailing wind and currents). And yes, if you strung out your fleet in a line, you could keep an eye on several hundred miles of ocean.

But mostly they floundered around a lot. Perhaps the most famous example I’m aware of is Nelson’s pursuit of the French fleet in the run up to the Battle of Trafalgar. They knew the fleet was out but had no idea where they were going, even though it was quite a large fleet for the time (20 something capital ships and probably a bunch of smaller frigates and support vessels) So Nelson just sailed on his best guess and ended up in the West Indies. As the battle of Trafalgar was fought off the coast of Spain, you can see how good a guess that was.

:smack: 

Right – you always make the stupid mistakes.

1914 was long before rada and staellites. In that time, it was pretty difficult to locate the enemy. take the Battle of the Falklands". A german cruiser squadron was on its way from the pacific, crossing into the South Atlantic . The german ships intended to attack the falklans-unbeknownst to them, a British fleet 9with battleships sporting 12" guns) was parked in Stnley Harbor. Suppose the germans never went within sight of Port stanley? Would the British have evr found them?
of course, there wasn’t any place for the germans to flee to-I doubt they ever would have made it back to the baltic Sea.

Intersting. So let’s say we have a one on one situation. If you are tracking a ship crossing the Atlantic, and he has a

Sorry, cannon went off early there.

So let’s say we have a one on one situation. You are tracking a ship crossing the Atlantic, and he has a few days headstart on you, but you have a faster ship. You know which port he is going to and where he is sailing from. Would you have a good chance of finding him before he gets to port? How wide are the shipping lanes, and how far could you see from the mast? I figure you have at least a one third chance of missing him at night, so that hurts you (if he is running dark) Also, it would seem you would never know if you already passed him or not, you would only have one shot.

The distance to the horizon is sqrt( (h+r)[sup]2[/sup] - r[sup]2[/sup] ), where h = height of the observer and r = radius of the planet. This can be reduced to sqrt(2hr) if one assumes that h is trivially small compared to r.

For example, the horizon distance from a 30m height is about 20 km.

For ships, the maximum visibility distance is the sum of the horizon height for your lookout plus the horizon height for the top of the other ship (i.e. two ships with 30m crow’s nests could see each other at 40 km, assuming that you need to see at least the crow’s nest and upward of the other ship to recognize it).

As said, predictable patterns based on wind, the current and tides going in and out of ports are the biggies. Having good maps and charts help. Knowing where the reefs and sandbars and other obstructions are help knowing from which direction you need to enter or leave a port.
Zig zagging always helps increase the odds of how much ocean you can cover. Not much maybe, but every little bit helps. Talking to other ships is an option. You see a fishing boat or whaler and ask, hey buddy you see anybody else come floating by here lately?

One of the biggest “misses” of all time was in 1798 when the French fleet was sailing to invade Egypt and the British fleet, commanded by Nelson, tried to intercept them. The British missed the French at sea by a matter of only a few miles. They eventually caught up with the French and attacked their fleet but by then they had landed their troops in Egypt. The British had a much better fleet and would almost certainly have annihilated the French fleet in an open battle is they had gotten a little luckier and found them while they were still sailing. And if the British had sank the French fleet at sea, the commander of the French army, Napoleon Bonaparte, would have probably been among those killed.

I dunno about having a “much better fleet”. Sure, Nelson annihilated the French fleet eventually at the Battle of the Nile, but he had every conceivable advantage during the fighting. The French were anchored in a bay and didn’t think there was room for Nelson’s ships to sail between them and the shore, and so their ships weren’t even cleared for action on the port side, which is where the head of the Royal Navy line went. It was late in the day, the French were taken completely by surprise, expecting the British to wait till morning to engage. The French line was pointed directly into the wind, so when the head of the French line was engaged, the ships to the rear could do nothing to assist. And it certainly didn’t hurt (or help, depending on one’s point of view) that the magazine on the 120-gun triple-decker L’Orient exploded.

Yes, the British had the advantage of better seamanship and gunnery, and those advantages along with Nelson’s genius would likely have led to a British victory in an engagement at sea, but it’s rather unlikely that it would have been as lopsided as the actual Battle of the Nile turned out to be. The fleets were pretty evenly matched on paper. Nelson had 14 of the line, but nothing very large. 13 74s and one 50 (really, a 50 at that point scarcely qualified as a ship of the line). The French had 13 of the line including the aforementioned 120, 3 80s, and 9 74s, plus 4 frigates.

That doesn’t sound right. You’re saying that a person on a 90ft. tower can only see the horizon twelve miles away?
I absorbed a bit of trivia, sometime in my past, that said a six ft. man standing at the waters edge could see approximately twelve miles.

Steve MB is right. From 6ft above sea level you can only see 3.3 statute miles.

Horizon Calculator

I believe it was Hornblower and the Hotspur, the book where Hornblower was a commander. They were searching for the Spanish treasure fleet from the New World because British intelligence had discovered that Spain had signed a secret agreement to ally with France. It was decided to seize the fleet and take the treasure into “safe keeping” rather than let it fund the French war effort. Everyone in the British fleet assigned to the interception is drooling at the thought of the prize money the Spanish fleet is worth. But Hornblower, at one end of the interception line, spots a Spanish warship that could attack the fleet unawares and leaves the main engagement to draw it off. Later though, it turns out that since Britain and Spain were not technically at war during the incident, no one gets any prize money anyway. But Hornblower finally gets his promotion to post captain.