Navigation in real life

[xXNightEagleXx]

I was wondering how did submarine found its own position in real life. I mean in the game we have a map that show us our location, but i don't think that at the time there was something like that. Aircraft did use visual reference but in the middle of the ocean .... how? (ok i know about old methods like stars bla bla bla, but i guess that it wasn't used anymore).
Dead reckoning can lead to errors on a long run without reference......So please enlighten my ignorance.

[Crannogman]

Originally Posted by FuriousEagle

I was wondering how did submarine found its own position in real life. I mean in the game we have a map that show us our location, but i don't think that at the time there was something like that. Aircraft did use visual reference but in the middle of the ocean .... how? (ok i know about old methods like stars bla bla bla, but i guess that it wasn't used anymore).
Dead reckoning can lead to errors on a long run without reference......So please enlighten my ignorance.

Pretty sure it was a combination of dead reckoning, chronometer, sextant, and landmarks

[ColonelSandersLite]

What he said.

Also, sorta in the landmarks categegory but not really is radio direction finding. You can triangulate your position if you have 2 or more different radio beams with known origins.

[Crannogman]

Believe it or not, even GPS satellites use a space-facing camera for back-up stellar confirmation of their own location

[Sailor Steve]

Originally Posted by FuriousEagle

(ok i know about old methods like stars bla bla bla, but i guess that it wasn't used anymore)

Those methods were indeed used, right up until recently. It wasn't until 1997 that the US Navy stopped teaching celestial navigation. In today's modern world of Global Positioning Satellites the sextant is redundant, but seventy years ago it was all there was. Yes, you could use Radio Direction Finding, but that depended on having two different stations within range, and knowing exactly where those stations were, something rarely available in the middle of the ocean. Even in the 1950s large aircraft had glass domes on top specifically for the navigator to use a sextant for sun and star sightings.

During World War II those "stars bla bla bla" were all they had, and the best method of navigation known until computers came along.

[CCIP]

One thing that bears mentioning is that maybe the main navigation instrument was and remains the gyrocompass - the trick is that the gyrocompass doesn't tell you your position, only how far you travelled and in what direction. Submarines at that time carried gyrocompasses.

The trick is that over time, a gyrocompass is prone to error and drift, so you need regular fixes to update your precise position and compensate for gyro errors. In familiar territory, as already mentioned, you had a variety of sources - including visual navigation and radio beacons. But out at sea, as Steve mentioned, until very very recently, there was no more accurate method of getting a precise fix than celestial navigation. Until GPS became fully operational in the 1990s, it remained the best and most accurate method. As late as the 60s, it was still the only real navigational reference for aircraft flying long distances over oceans (before gyrocompasses that were both light and accurate enough were developed, and became basis for automated inertial navigation systems). So yes, celestial navigation is no longer used - but it was in fact not until the 1990s that technology to fully replace it actually existed, although more drift-resistant, portable gyroscopes, navigational computers and better radio navigation lessened reliance on it over the years.

To this day, all precise navigation in fact continues to rely chiefly on inertial gyros, which provide much faster and smoother tracking than radio signals, which are prone to interruptions; GPS and other sources are simply used for regular automated corrections to these gyros. It's not actually all that fundamentally different from how ships operated back in the 1940s - the difference is that the source for fixes is weather-independent and the process of updating the fixes and calibrating the gyrocompasses is fully automated, removing some of the human error from the equation.

It's also worth noting that celestial navigation is still extremely accurate. Not quite to the level of GPS, but a lot closer than one might think. It's just slower, involves more work (either for a human or a computer) and weather-dependent.

[xXNightEagleXx]

Well guys thank you. Is there any ship simulation that simulates celestial navigation? XD I would like to give a try.

[CCIP]

One thing that's good to remember, though, is that this wasn't the captain's job - it was the ship navigator (and his assistants) that took the measurements. There are "real navigation mods" for SHIII and iirc SHIV. I've never tried them - what I would personally rather see in SH instead is just a margin of error introduced into navigation. Otherwise for me having to take measurements as captain of the ship is as much a simulation as running around inside the boat hitting things with a wrench to stop leaks

[BigWalleye]

Originally Posted by CCIP

One thing that's good to remember, though, is that this wasn't the captain's job - it was the ship navigator (and his assistants) that took the measurements. There are "real navigation mods" for SHIII and iirc SHIV. I've never tried them - what I would personally rather see in SH instead is just a margin of error introduced into navigation. Otherwise for me having to take measurements as captain of the ship is as much a simulation as running around inside the boat hitting things with a wrench to stop leaks

SH5 has a really good implementation of "real navigation." Own position is not shown on the nav map. At regular intervals and when ordered, the navigator takes a sighting. Of course,the boat must be surfaced amd the weather clear. Then it takes a variable length of time for him to work up his sighting. His accuracy and speed depend on his skill. When he's done, your estimated position is marked on the map. For a faster result, the navigator will do a DR from the last celestial fix. The error of the DR plot increases with time from the cel fix. The Kaleun doesn't actually do anything - except worry about where his boat really is.

This is one of many things I find really good in SH5. Unfortunately, for me it still lacks flavor. Not enough U-52, too much NCC 1701.

[Rockin Robbins]

One area related to celestial navigation DID influence the Captain and we have no analog in the game. That area is error mitigation.

If you are especially good with a sextant, and if your clocks are bang on, your error on a small boat or submarine would likely be in the range of 50 miles. So if you're headed to a port do you sail right at it?

No, you don't. Suppose the port is on a north-south coastline and you navigate straight to it. Here comes the land and......what the hay? No port. Okay, hotshot, which way do we turn? Flip a coin. Ask the exec. Spin a bottle. Doesn't matter if you used a modern computer, its answer would conform to Murphy's law--you turn the wrong way.

The correct way to plot a course is to purposely steer a bit further to the north or south than the size your error envelope. If you are within plus or minus 50 miles, then aim 50 miles north. Either you see the port as you approach or you know you must turn south. Error envelopes change with sea conditions, the length of time since the last valid sighting, skill of the navigator.......

[merc4ulfate]

If you know where you are then you start there and given speed and heading you can know where you are going. The sextant should be used. There will always be errors due to current and wind speeds either adding to or subtracting from your speed so you may be pushed off course a tad.

When I was a helmsman we used two tools to navigate the helm. We had a gyrocompass which gave us true N,S,E,W and we had a compass. Depending on where you are on the earth your heading will be adjusted due to flux in the magnetic field.

A course might be give to steer 345 by 352. One would be your gyroscope heading and the other your magnetic compass heading. If the two did not line up then something was amiss in navigation. There is an offset in heading depending on where in the world you are. I remember our Lead navigator was a 1st class petty officer using the sextant at night to check our position. Over him was an LTJG and the XO a LT.

The XO ran us aground. The 1st class petty officer got us where we were going safely.