How Did We Manage Before GPS?

John Cassels
6th November 2005, 19:56
Couple of weeks ago, bought one of these compact flash receivers for 68 euro and only the size of a fag packet
for use with the laptop. After seeing my position given to three decimal
points after the minute, got to thinking how it used to be ....
in the days when "Board of Trade"was still stamped on your ticket
Anyone reading who was 2nd.mate at the beginning of the 70's will
remember...............

You did the 12-4 and crashed around 0530 after a few beers with the
3rd.engineer. Called 3 hours later and up to bridge clutching bacon
butty. Made cup if tea,finished butty,wound cronometer,grabbed sextant
(assuming the various errors hadn't changed since the last time you checked in spite of being bounced in and out of box) ,went to bridge wing hoping you would be able to see the sun and horizon and preferably both at the same time. Took your 3 sights while trying to
keep your balance on a bridge wing rolling and pitching all over the place. Then surrounded by bits of paper and a well worn dog eared
copy of Norie's Tables using a height of eye correction which bore no resemblance whatsoever to high the bridge wing was when you took the sights. Got your p/l ,ran it up to noon, couple of G and T's , had lunch,then back up for noon sights. Got latitude, ran it to noon,adjusted
morning p/l and bingo , position where the ship was at noon. Secretly,you knew the ship was no where near the position but you hoped that she was at least within a couple of miles of it.

Now,yesterday,35 years further on , I plugged a piece of black plastic
into the PC, pressed a few buttons, had a fag, and meantime a position
accurate to about 5 meters appeared.................

Don't really need a GPS , but for me it's pure , shameless facination
especially when you think how it used to be.

--------------------
expat

R798780
6th November 2005, 20:32
Yes, memories.

And in the quiet of the afternoon watch took Venus on the meridian, crossed it with the sun and, on occasions, with a complimentary moon. Then we knew where we were.

The mate had taken stars one morning, timed himself with a stopwatch, I just counted the way back to the chronom. Got to noon, got a position, The old man Sam B. liked it. He "didn't believe we were where the mate put us". Not the best loved mate in the company!

Mid '80s we got sat nav. A pass every hour and a half if we were lucky and if the machine didn't reject the pass on "too many iterations" or some other excuse. Then when you really needed a fix there wasn't a hit for maybe ten - fifteen hours. Out with the sextant, it didn't run out of batteries either. But it was interesting to see how close we got with sun sights and stars when we did get a good pass on the electric job.

John Cassels
6th November 2005, 21:37
Sorry all, should have titled the post
"How did we manage before GPS"

John Cassels
11th November 2007, 10:45
Now , more than two years later , laptop has thrown a wobbler so have just
bought one of the latest generation GPS handheld recievers. No maps or
anything , just the basic course , speed and position to within 3 - 5 meters.

As in my first post , the facination still remains remembering what we used to
have to do to get the same info 40 years ago.

Moulder
11th November 2007, 11:34
All that and now you ex-mates and engineers can even talk to people the other side of the world without learning morse - ah technology!

Steve.
(Thumb)

trotterdotpom
11th November 2007, 12:04
At least you could have a couple of beers at 4 AM and a couple of gins before lunch and no-one gave a fig. Wonder what they do with all the spare time gained from having a GPS?

John T.

Moulder
11th November 2007, 12:22
At least you could have a couple of beers at 4 AM and a couple of gins before lunch and no-one gave a fig. Wonder what they do with all the spare time gained from having a GPS?

John T.

Drink more beer!

Steve.
(Thumb)

K urgess
11th November 2007, 13:30
Not allowed.
They probably get breathalysed before going on watch today.:sweat:

johnalderman
11th November 2007, 13:53
Isn't it funny how some mates managed to get six star sights to cross perfectly on the spot!!!!!!!!!!!Almost impossible I would say, but some managed it nearly every morning.

K urgess
11th November 2007, 14:08
Creative navigation is an art form just as is creative accounting![=P]

Steve Woodward
11th November 2007, 14:10
Still have my sextant ( Heath MC1) and will never part with it, last used it two years ago taking stars crossing the north sea, came out with a good position but it was for old times sake to see if I could rember how, moving round the boat was a pain with sails or rigging joining in!.
Give me a GPS anyday, reliable in all weathers or cloud types, nostalgia is great - but knowing were you are at any time is better.

James_C
11th November 2007, 14:14
LOL John. With me it was normally a case of it being completely overcast at twilight, then once the sun was up the sky would clear to a brilliant blue - just in time for the Old Man to appear for his morning cuppa.

"Didn't you get stars this morning?"
"eh, no Capn it was overcast"
(Old Man looks out the window)
"Hmm"

It could happen to anyone, but it always seemed to happen to me.
LOL

gdynia
11th November 2007, 14:16
Isn't it funny how some mates managed to get six star sights to cross perfectly on the spot!!!!!!!!!!!Almost impossible I would say, but some managed it nearly every morning.

Jack

It was always down the the thickness of your pencil point(Thumb)

randcmackenzie
11th November 2007, 16:29
At least you could have a couple of beers at 4 AM and a couple of gins before lunch and no-one gave a fig. Wonder what they do with all the spare time gained from having a GPS?

John T.


They fill in forms and check lists.

johnalderman
11th November 2007, 16:40
I always got the old cocked hat, then closed my eyes and stabbed with the old 2B and Bobs your uncle.

John Cassels
11th November 2007, 20:22
Rather unfortunate that my thread has not generated any rational input so
far.

AncientBrit
11th November 2007, 20:51
Rather unfortunate that my thread has not generated any rational input so
far.

One should bear in mind at all times, that to assume that one will recieve an intellectually uplifting response to ones mundane daily pontifications; is to assume that others share the depth and clarity of mind and purpose so plainly exhibited by the omnipotence of our original statement(Smoke)

Geoff_E
11th November 2007, 21:04
That's a bit unfair John. It's mostly been rational, if fairly light-hearted. I think, deep down, most would admit to a great sense of satisfaction. It was, and where still practised, is still, an art form. It was also something one grew into as there was never any real teaching at college about the use of a sextant. (By that I mean the accurate manipulation to sit the lower limb of the sun, or a star just on the horizon.)

Yes GPS is here to stay but I'm afraid that those who have never known any other are much the poorer for it.

I inspect quite a few vessels for our "Clients", most of whom wouldn't know a good ship from a bad one if it ran them down! All too often, when I ask if they actually have a sextant on board (after the blank looks!) I'm shown one, immaculate, straight out of the box. If I'm in a bad mood I've been known to ask if they've ever checked for errors. (Grumpy old man!) Mostly it's not worth the effort.

I would also refer readers to a recent thread touching on the quality of officers/insurance premiums on vessels, etc.

Now, what is the time of "Noon"?

Dick S
11th November 2007, 21:43
Times change,
Was at sea when SATNAV was just in, never had the pleasue of GPS to help me out. There was a great satisfaction of getting sights right and picking up a good landfall after a long passage. (North Atlantic winter on 25kt container boats with only loran or decca makes you wish GPS was there then!) with the reduction of manning levels and the new regulations and subsequent form filling I wonder if there really is time for sights these days.

But that was my time - I like many people - lived it and enjoyed it. I hope that present seafarers can say the same 20 years after they 'swallow the pick'

Dick

3knots
12th November 2007, 08:55
A couple of years ago I decided to come accross the Pacific from Panama to Tang Gu the old fashioned way. I gave the mates a month to brush up their techniques, which involved a lot of lessons by me! The second mate (Filipino lad) actually told me that navigating with a sextant was very dangerous! We set off with both GPS's taped over so no one could cheat, and after a couple of days of doubting and slightly insolent stares things started to change as they got used to the old ways. Our first landfall on Hawaii was closely watched by all, and when we got a fix from radar we were pretty close to our DR. By the time we got to a landfall on the islands south of Japan the whole atmosphere had changed - I had converts who really felt they had achieved something. The question is, of course, what would we do if both GPS sets go on the blink?

John Cassels
12th November 2007, 08:58
Rather unfortunate that my thread has not generated any rational input so
far.


You're right guys , sorry. Can't expect everyone to share my point of view.

Will gladly retract my above statement.

Skye Sierra
12th November 2007, 12:32
Secretly,you knew the ship was no where near the position but you hoped that she was at least within a couple of miles of it.

--------------------
expat

I did pre sea training at Blythe Street in Belfast in '66 where navigation was taught by Capt. 'Kit' Carson a tremendous wee character who taught me a great deal. Following the final exams Kit called me in and told me that I had failed my navigation by 1% but he would give me the requisite pass mark if I took 'O' level navigation the next month. I thanked Kit and told him I would pass it for him.

"I know you will lad", said he, "navigation's not an exact science - it's an art"!

pentlandpirate
12th November 2007, 13:37
There was a time around 1981 when SatNav was installed on the ship. The old man insisted it would change nothing. Astro sights had to be taken as normal, dawn, noon and dusk........to check the satnav was working!

Chouan
12th November 2007, 16:18
The approximate art of finding out where you've been.

pentlandpirate
12th November 2007, 16:21
The approximate art of finding out where you've been

The approximate art of finding out where you THINK you MIGHT have been

non descript
12th November 2007, 17:54
Sorry all, should have titled the post
"How did we manage before GPS"

Edited the title accordingly.

(Thumb)

Cap'n Pete
12th November 2007, 20:00
There is a view that GPS is the navigation aid of choice of the badly trained navigator. However, my view is that GPS is a valuable navigational tool which has to be used properly and this can only be achieved, like everything else at sea, after receiving proper training.

I always make sure all my officers continue to practice using the sextant, and all other available means of fixing the ship's position both on coastal passages and deep sea. However, I demand the same standards of excellence in using the sextant as I do the GPS. Any navigational aid in the hands of an idiot is dangerous.

tacho
15th November 2007, 15:30
immaculate, straight out of the box. If I'm in a bad mood I've been known to ask if they've ever checked for errors.

So they knew how to take it out of the box then..?!

carcar
15th November 2007, 17:00
Can anyone be kind enough to tell me how the ancient Greeks,the Vikings,and the Romans found their way without the sextant,never mind the GPS
chas R802892

Chouan
15th November 2007, 17:26
The Greeks and the Romans did it by sailing coastal, virtually never out of sight of land, stopping at night, only doing short hops between islands etc when they were otherwise out of sight of land, based on prior experience. The Romans' seamanship was in any case poor, losing hundreds of ships and thousands of men to storms, shipwrecks etc whilst fighting the Carthaginians. The Vikings were capable of ocean navigation, using stars to steer by, apparently.

JoK
15th November 2007, 17:51
I read somewhere that on 911 the Americans threw an error into the GPS system of 100 m or more? Being an engineer,that only caused me to look upon it as even more hocus pocus in a small black box!

Sister Eleff
15th November 2007, 21:22
There was a time around 1981 when SatNav was installed on the ship. The old man insisted it would change nothing. Astro sights had to be taken as normal, dawn, noon and dusk........to check the satnav was working!

A bit like me when first using a calculator. I would add up a column of figures with the calculator then do it manually to check the calculator. If there was a difference, my immediate reaction was to blame the machine - that is until I checked it again - it didn't take too long to learn to rely on the calculator!! Mind you I will still check it again ... with the calculator.

tedc
16th November 2007, 20:43
Hi John!

Yes, Satnav on a ship must be great!

However, there are many stories of landlubbers, who have satnavs in their cars, ending up in all sorts of strange places - there's a river "ford" not too far away which had a couple of cars in over their roof because the satnav took the shortest route.

There' be hell top pay one day when a socking great tanker finds itself coming up one of these little streams!!!!

That should put a smile on some motorist's face!

sparkie2182
16th November 2007, 21:48
the american department of defence has the ability to introduce ultra high accuracy for their own military purposes, and simultaneously degrade the accuracy of civilian gps recievers..... this can be done at will....at any time.
this was noticeable during the first gulf war, when i was using differential gps for survey purposes, the results were useless.
only later did i learn why.


best regards to all...............

slick
17th November 2007, 04:53
All,
Hence "Galileo".
Yours aye,
Slick

sparkie2182
17th November 2007, 21:29
if it ever gets off the ground, slick.

http://news.bbc.co.uk/1/hi/sci/tech/6634285.stm

all very predictable.

John Cassels
4th December 2007, 09:51
Was trying out the new GPS at the weekend. Stood in the back garden and
marked my position. Then wemt to waypoints and punched in the position
of Gourock pier head. Pressed another button and the screen gave a
distance of 865.4 KM on a heading of 319 deg.

Since the initial position was satellite generated , have I now got a great
circle distance and initial course ??.

tacho
4th December 2007, 14:33
Imagine how much worse the skills shortage at sea would be if they suddenly had to find a bunch of people who could still navigate traditionally. Not to mention radar watchkeeping sans ARPA.

Orbitaman
4th December 2007, 14:48
Imagine how much worse the skills shortage at sea would be if they suddenly had to find a bunch of people who could still navigate traditionally. Not to mention radar watchkeeping sans ARPA.

Probably not much worse than it is now. A vast majority of Officers from a number of regions around the world cannot navigate traditionally as it is, so the situation wouldn't change.

Without ARPA, it is likely that the number of collisions is likely to remain the same. Most of todays watchkeepers believe what they are being told on a radar screen over what they can see with the mark one eyeball out of the bridge window. Without the readout to tell them what is happening? they will start to use their eyes again to assess the situation.

David Davies
4th December 2007, 19:46
How did we manage before Sat Nav? The question is only relative, how did we manage before the sextant, the chronometer, radio time sinals and the Nautical Almanac? I only spent 15 years in the MN , finishing in 1963 but during that time I served in some ships on long passages without the benefit? of either radar, gyro or even a echo sounder, we did the job and took a pride in doing it. After 1963 I became a "yotie" for nearly 30 years , sailing off shore and continuing to use my sextant and Burton's 4 figure log tables when necessary. During this time GPS or Sat Nav became available but I declined to use it on principle, rightly or wrongly? I often wondered ,on a similar vein, how did they manage before the sextant so I made my own Davis's quadrant 1598? (it's my avatar, Davies's quaqdrant) and got latitudes to withinn 5 minutes What abou the Nautical Almanac? With a large mariner's quadrant made from a redundant bath panel one could observe the upper and lower meridian transit of a circum polar star and get a good latitude (this is carried out ashore)With this latitude one gets the declination of every body as it transits the meridian, you could also get it's right ascension if one could record time.I must admit that it would take 4 years to get the sun right. That solved the latitude problem, longitude was a different matter and we had to wait for the sextant 1729? To be able to find the error of our primitive clock or latter Mr Harrison's chronometer (rateable error or not) one had to understand the intricities of the lunar distance using Napier's logarithms simplified to base 10,common logarithms for common seamen!. Finding logitude ashore was accomplished by using the moons of Jupiter. My limited experience compiling lunar distance tables from a 2000 Nautical Almanac price £28, they used to be 5 bob gave a GMT to within 28secs, assuming that the BBC pips were correct equated to a longitude error of 7 minutes equal to 4 miles in our latitude . To me asking the question "how did we manage before " lead to a long and all consuming exercise. Our forebears did the job using these methods as their forebears did using a selection of knotted cords relevant to selected stars and land falls. Technology leads to greater accuracy and greater safety, or we hope it does, as it has done throughout the ages

Geoff_E
4th December 2007, 22:04
"With a large mariner's quadrant made from a redundant bath panel...."

Does the colour affect the accuracy?

Chouan
4th December 2007, 23:45
"With a large mariner's quadrant made from a redundant bath panel...."

Does the colour affect the accuracy?

Rather reminds me of an incident whilst arriving at the entrance to the Maas on the "Solvent Discoverer", John Conn as Master. The Control had identified us on their radar, told us our position, course, speed etc. The Old Man said how impressed he was. "Yes", said the "Maas Control, we have a very sophisticated electronic control system that tells us everything". "What colour are we then?" said the Old Man.

G0SLP
5th December 2007, 00:13
Departing Dakar for Point Noire in June/July 1999, a few weeks before the GPS roll-over, our Old Man decided to test out our newly aquired Russian Deck Officers' navigational skills. (We'd just had our British & Sri Lankan Officers replaced, leaving just the Master & Chief to 'hold the fort', as it were). He got me to pull the fuses to the GPS sets, & told the mates that they were going to do things the 'old-fashioned way'. This, as you can imagine, caused a few long faces.

12 hours later, the Old Man went to the bridge to enquire as to where we were. He was given a good position, so enquired from the OOW which stars he'd used, how easily he'd found the calculations etc. When told 'no problem Captain, I've just asked the ship over there where we are', the excrement hit the wind-propelling device!

Good spectator sport, but my fridge was DEFINITELY collateral damage...

Sarky Cut
5th December 2007, 01:12
If I may make a very small comment on all the above, "my life in your hands"!

I'll get my coat!

tacho
5th December 2007, 14:18
I'm in the process of reading "Stand By For Action" by Cmdr William Donald.

The reminiscences of a WW2 destroyer captain escorting colliers mainly up and down the East Coast. They could certainly have benefited from GPS. Apparently they navigated by lit buoys every 5 miles or so. The E boats would occasionally tie up to them in wait !!

David Davies
5th December 2007, 16:54
The reminiscences of a WW2 destroyer captain escorting colliers mainly up and down the East Coast. They could certainly have benefited from GPS. Apparently they navigated by lit buoys every 5 miles or so. The E boats would occasionally tie up to them in wait !![/QUOTE]

Many years ago I was told by a retired naval officer involved with these convoys that the E-Boats were not the only threat. Our own minefelds claimed quite a few casualities including escorts. The worst incident occurred when when the North bound convoy met the South bound convoy in Happisburgh Gat at night

John Cassels
5th December 2007, 20:15
Can anyone still tell me if my GPS is giving a great circle or RL distance ?.

tacho
5th December 2007, 20:30
You could check by comparing tracks between a couple of distant points. i.e. Co & Dist A to B and Co & Dist B to A.

The diff should be convergency. If they're just reciprocals it's a Rhumb Line.

Bill Davies
5th December 2007, 21:48
Impressed!!

Gulpers
5th December 2007, 22:33
John,

GPS calculates a Great Circle distance although, for my trips in the Irish Sea, it's immaterial whether it's a CG or RL. (Thumb)

LEEJ
6th December 2007, 08:19
It should tell you in the menu/settings

John Cassels
6th December 2007, 09:04
Thanks eveyone . Now I can check what DFDS do when we come across
next April.

Cap'n Pete
6th December 2007, 22:34
John,

GPS calculates a Great Circle distance although, for my trips in the Irish Sea, it's immaterial whether it's a CG or RL. (Thumb)

On all the GPS units I've sailed with, you have a choice between GC or RL courses and distances. However, it's either one or the other so on a passage with a combination of GC and RL tracks, the GPS will not give you the actual distance to steam. If the next track is GC or vice-versa, you have to change the preferences. This is a pain as the total distance to go is never correct until all the tracks between the remaining waypoints are either RL or GC.

demodocus
6th December 2007, 23:09
you have to change the preferences. This is a pain as the total distance to go is never correct until all the tracks between the remaining waypoints are either RL or GC.

So, GPS won't calculate distance to go on a Composite Great Circle. A nice exercise for the Second Mate to program the equations and waypoints into his laptop. Then you'd get DTG in less than a second.

We did a similar thing around the world with Bank Line. Laptop, Electronic Ephemeris, sextant, and a good watch produced a 5 star fix in less than 5 minutes.

Now if they could get the GPS to make cocoa .......

Gulpers
7th December 2007, 00:34
On all the GPS units I've sailed with, you have a choice between GC or RL courses and distances. However, it's either one or the other so on a passage with a combination of GC and RL tracks, the GPS will not give you the actual distance to steam. If the next track is GC or vice-versa, you have to change the preferences. This is a pain as the total distance to go is never correct until all the tracks between the remaining waypoints are either RL or GC.

The "big ship" fit is obviously more up market than my Garmin GPS and Lowrance Chartplotter! (==D)

John Cassels
7th December 2007, 10:44
Boy , a Garmin AND a lowrance plotter.

Not bad Ray, you could easily make it over to my neck of the woods !!.

LEEJ
7th December 2007, 11:51
One of the dangers of using GPS was demonstrated to me on a passage between Liverpool and Dublin. A passenger approached the Chief Officer mid way and noted that the ship according to his GPS was several miles off track. The mate pointed out that if we were to follow his navigating skills then we would be passing through the middle of Angelsey!

Gulpers
7th December 2007, 22:44
Boy , a Garmin AND a lowrance plotter.

Not bad Ray, you could easily make it over to my neck of the woods !!.

Given decent weather John, yoy never know! (Thumb)

Gulpers
7th December 2007, 22:49
One of the dangers of using GPS was demonstrated to me on a passage between Liverpool and Dublin. A passenger approached the Chief Officer mid way and noted that the ship according to his GPS was several miles off track. The mate pointed out that if we were to follow his navigating skills then we would be passing through the middle of Angelsey!

Lee,

Helluva glad you weren't in the middle of Anglesey - I'd have had a rather busy time at work! (EEK)

Most of the GPS problems I've encountered are due to owners not understanding the "setup" procedure! [=P]

Tom S
8th December 2007, 11:40
John,
I was trawling through the web last night when I came across this entry thought it might tickle your fancy!!!
You are lost on a desert island
with a sextant, a chronometer, a carrier pigeon,
and your copy of Smart's Spherical Astronomy.
Explain how you will save yourself.
(Assume that the chronometer is keeping GMT,
and that you know the date.)

Step 1: determine your latitude.
There are (at least) two possible techniques.

1. Measure the altitude of Polaris above the northern horizon, using the sextant.
This is approximately equal to your latitude.
(Polaris, the "North Star", lies very close to the North Celestial Pole.)

There are various problems with this.
Firstly, if you are in the southern hemisphere, Polaris will be below the horizon!
Secondly, you need to carry out the measurement in nautical twilight,
while it is still light enough to see the horizon,
and Polaris is only a second-magnitude star,
so it may not appear bright enough to measure accurately.
Thirdly, Polaris does not lie exactly at the North Celestial Pole,
so your result could be nearly 1 degree in error.

2. So, as an alternative,
measure the altitude of the Sun at midday, using the sextant.

Knowing the date, calculate the declination of the Sun
(it varies sinusoidally,
with a period of 1 year starting at the spring equinox,
and an amplitude of 23.4 degrees.)

The midday altitude, when the Sun is on the local meridian,
is composed of:
the height of the celestial equator above the southern horizon (equal to the co-latitude)
plus the height of the Sun above the celestial equator (its declination).
(If you are in the southern hemisphere,
the celestial equator will be closer to the northern horizon;
in this case its distance from the southern horizon, the co-latitude,
will be greater than 90°.)
Knowing the altitude and the solar declination,
calculate the co-latitude and hence the latitude.

If the sextant can be read to an accuracy of a few arc-minutes,
you should correct your reading for refraction.
The apparent zenith angle of an object z' is greater than its true zenith angle z
by the value k tan(z'), where k is approximately 1 arc-minute.



Step 2: Determine your longitude.
Again there are (at least) two possible techniques.

1. During nautical twilight,
if you can locate a star whose celestial coordinates you know,
measure its altitude above the horizon using the sextant,
and note the time (GMT) using the chronometer.

Knowing the star's altitude, its declination, and your latitude (previously determined),
calculate its Hour Angle
by applying the cosine rule to "the" Astronomical Triangle.

Knowing the star's Right Ascension,
calculate the local sidereal time of the observation
(Local Hour Angle = Local Sidereal Time - Right Ascension).

Knowing the date,
calculate the Greenwich Sidereal Time
corresponding to the Greenwich Mean Time of the observation.
GST is equal to GMT at the autumn equinox,
and GST runs faster than GMT by one day in 365.25 days.

The difference between the Local Sidereal Time (from your observation)
and Greenwich Sidereal Time (from the chronometer)
is your longitude east or west of Greenwich.

2. Failing a star with known coordinates, use the Sun.
Note the time (GMT) when it reaches its greatest altitude:
this is midday, Local Apparent Time.

Use the formulae given in Smart's Spherical Astronomy
to calculate the Equation of Time on that date.
(Or derive it from first principles:
allow firstly for the non-uniform motion of the Sun around the ecliptic (Kepler's Second Law);
then allow for the fact that the ecliptic is tilted to the equator.)

Add or subtract the Equation of Time to your Local Apparent Time,
to obtain Local Mean Time.
The difference between Local Mean Time and GMT
is your longitude east or west of Greenwich.



Step 3:
Tear a strip of paper from the title-page of Smart's Spherical Astronomy
to write a message giving your latitude and longitude.
Launch it by carrier-pigeon and wait to be rescued!



This question formed part of the final exam at UCLA in 1961.
(Trimble, V., "The Observatory" 118, 32, 1998).

TomS

Chris Isaac
8th December 2007, 12:34
You would think that if you had managed to keep hold of a carrier pigeon you would have managed to remember to pack your GPS system as well!

David Davies
8th December 2007, 13:33
Two problems The pigeon will only return to its loft, maximum distance for a good bird 600miles. You can use any cicumpolar star if you have the time, but by that time you will have eaten the pigeon any way

Harry Grainger
4th January 2008, 23:18
Oh dear dear me, only a lowly engineer but I still remember coming through the channel on a gtv and a call on the talk back to the control room "passing the Varne" at least we passed it, didn't go on top of it at 22 kts. Has that got anything to do with sextants or GPS ???

vasco
4th January 2008, 23:56
we did this http://www.shipsnostalgia.com/showthread.php?t=15595 sort of :-)

non descript
4th January 2008, 23:59
we did this http://www.shipsnostalgia.com/showthread.php?t=15595 sort of :-)

Yes, and look where it got certain people (Jester)

sparkie2182
5th January 2008, 00:13
always remember to adjust the gps for index error........:)

R831814
3rd February 2008, 08:45
Not allowed.
They probably get breathalysed before going on watch today.:sweat:

Regular drug tests are also order of the day. What a life(EEK)

Philthechill
3rd February 2008, 12:03
What happens if you don't come-up-to-scratch with the drug-test, does the testing bloke then supply you with some to make sure you do? Tee! Hee! Phil(Hippy)

tacho
3rd February 2008, 12:58
My GPS is invaluable when doing Multidrop in London and so far the rhumb line great circle issue hasn't cropped up.........then again the North Circular.....?

Hugh Ferguson
3rd February 2008, 13:34
I remember a long drag from Fremantle to Durban in a low powered coal fired old steam-ship which must have taken quite a few days out of sight of everything, including other ships. Arriving off of Durban we steamed straight in past the Bluff without having to alter course. The A.B. at the wheel, Jimmy Newall, was so impressed with this feat of navigation that, when he came off the wheel, he shook hands and congratulated those of us who were on the bridge. You don't ever get a feeling of satisfaction like that from a G.P.S.!
I wonder if anyone remembers Jimmy.

lakercapt
3rd February 2008, 17:20
Got a GPS system for my Christmas and amazed at the details for even the remote country roads.
Travelled down to Florida last week using it. Wonderful except for that last 100 miles when I ended up travelling country roads in Alabama and Florida. Places the tourists don't normally see. It di however get us to the destination!!

JimC
3rd February 2008, 19:30
I went to sea in the early1950s. Everything we had was 'new' except the sextant of course! Shortly after my first trip I was told I had to go to Leith Nautical College and get a Radar Observer's Certificate. This was the time when Blue Funnel would not allow such 'things' as radars on their vessels. I returned to sea with my nice new bit of paper an was told by the old man 'forget it' these things are merely aids to navigation. Even the legal eagles had this opinion as did the Board of Trade. I was on one passenger vessel where the 'old man' had chippy make a contraption which covered the radar set entirely and was padlocked in place. If you wanted to use the radar; you had to call him no matter what time of day or night and he arrived on the bridge with the only set of keys. The joke was; I was the only one on board with the proper BoT certificate and the only one who knew how work 'the thing' properly!
I really liked taking sights and all that went with it. It was almost like a sacred ritualistic performance with the chief priest(the old man presiding) and certainly helped to pass the time on those very long two year trips we real sailors had to do...(head down and waiting for it!).
The advent of GPS has been a boon and is just another 'tool' of the trade. I have only one mis-giving about it. It relies on sattelites which - in most cases are beyond the control of us or shipowners. What happens when the politicos decide it might be a good idea to shut the system down ?
The bottom line is that in every generation you will get those who say " new fangled contaptions make these young whippersnappers lazy". What will happen if? All I can say is 'Viva the bolshies who persevered against all odds to help things to move forward out of the dark ages'. Please don't bring back the astrolabe!!

Jim C.

AncientBrit
3rd February 2008, 20:43
The Grey Funnel was always said to err on the side of excess and navigation was a definate instant in that regard.
Most warships were issued one chronometer and 6 deck watches, all to be wound a specified number of turns per day. Out of sight of land it was morning and evening stars and noon meridian daily.
After noon meridian was finished it was time to take out the Star-globe and note the bearing and angle of chosen stars for evening sights, half hour before sight time off to the radio room with the working deck watch for a time check, this was noted daily on paper inside case, back to chart-house and check the chronometer and other deck watches and note the errors.
Phone the wardroom to remind N.O. (Navigation Officer) that it was stars time and meet him on bridge with sextant, deckwatch and list to tell him where the stars were going to be. We always took at least 5 stars and sextant readings were noted against uncorrected deck watch time on N.O's "mark".
While N.O. done his paperwork I would figure out on the Star-globe the stars for morning stars....which in the tropics could be three to four hours later at best. The only good thing about this excess was that on a carrier, after evening stars you could go down to the galley and qualify for lunch at midnight with the flight deck Airy Fairies and the smell of fresh baked bread and bacon frying will forever remind of morning stars.
In my time the latest navigational wizardry was the Decca Navigator, but I wouldnt have missed all those amazing sunrises and sunsets for the world.
Plus there a feeling of mythical magnificence when you can stroll on to the bridge and tell the OOW that Tristan da Cunha WILL appear on radar, bearing 024 degrees during the morning watch!
AB

sparkie2182
3rd February 2008, 21:59
upon removing the top cover of the "decca navigator", the unwary radio officer was confronted with the words.........

"RADIO OFFICERS ARE NOT TO REMOVE THIS PLATE"

stencilled in the chassis top plate, thereby denying us the right to play with it................

:)

PollY Anna
4th February 2008, 11:22
I am interested with all the above comments BUT I don't recall turning up at the wrong port the officers always seem to find the right place so somebody was doing it right. and it was all done with the sextant, the GPS and Sat Nav were a long way off in the future.

slick
4th February 2008, 12:16
All,
Nories or Burton's?, some people latterly used a new fangled sets of Tables Myerscough and Hamilton any observations?
Yours aye,
Slick

R893891
4th February 2008, 12:39
The closest I came to using anything 'technical' when I was second mate was LORAN (remember those?) and in home waters it was the DECCA NAVIGATOR. Otherwise it was all sextant work and land bearings (when us deep sea types dared get that close). Well I must admit we had radar, but there again only used when approaching land.

K urgess
4th February 2008, 12:55
Having just acquired a sextant, a battered copy of Norie's, an incredibly old copy of "Wrinkles in Navigation", a "North Sea Pilot" and an accurate chronometer, I'm ready for the day the roof floats off my house and I can sail away into the sunset.
By that time the satellites will have fallen out of the sky and I'll be equipped for anything. Provided I can get my head round the maths. (Whaaa)

John Cassels
4th February 2008, 13:53
Kris , just hope your roof floats off on an Easterly direction or els you won't
be needing the North Sea Pilot !!.

K urgess
4th February 2008, 16:51
Should do, John.
It's downhill in that direction. [=P]

SSimon
4th February 2008, 22:27
How did we manage before GPS?
We just did. We gathered information from wherever we could. Sights, soundings, bearings, horizontal sextant angles, DRs, anything.
I remember going regularly from Tanjung Priok to the South end of the Bangka Strait and, if it was cloudy, we even estimated where we were by the SMELL of the sea at each Sumatran river mouth as we went North. Each estuary smelled a bit different.

SSimon
4th February 2008, 22:30
Couple of weeks ago, bought one of these compact flash receivers for 68 euro and only the size of a fag packet
for use with the laptop. After seeing my position given to three decimal
points after the minute, got to thinking how it used to be ....
in the days when "Board of Trade"was still stamped on your ticket
Anyone reading who was 2nd.mate at the beginning of the 70's will
remember...............

You did the 12-4 and crashed around 0530 after a few beers with the
3rd.engineer. Called 3 hours later and up to bridge clutching bacon
butty. Made cup if tea,finished butty,wound cronometer,grabbed sextant
(assuming the various errors hadn't changed since the last time you checked in spite of being bounced in and out of box) ,went to bridge wing hoping you would be able to see the sun and horizon and preferably both at the same time. Took your 3 sights while trying to
keep your balance on a bridge wing rolling and pitching all over the place. Then surrounded by bits of paper and a well worn dog eared
copy of Norie's Tables using a height of eye correction which bore no resemblance whatsoever to high the bridge wing was when you took the sights. Got your p/l ,ran it up to noon, couple of G and T's , had lunch,then back up for noon sights. Got latitude, ran it to noon,adjusted
morning p/l and bingo , position where the ship was at noon. Secretly,you knew the ship was no where near the position but you hoped that she was at least within a couple of miles of it.

Now,yesterday,35 years further on , I plugged a piece of black plastic
into the PC, pressed a few buttons, had a fag, and meantime a position
accurate to about 5 meters appeared.................

Don't really need a GPS , but for me it's pure , shameless facination
especially when you think how it used to be.

--------------------
expat

You missed out having to fend off the wandering tea pot as the ship rolled while you were working on the figures :sweat:

Jim Moon
24th March 2008, 01:19
I remember in 1981 or 82 taking new ship from shipyard in Pusan and the DF needed "correctio curve" making up. Naturally me (R/O), 2nd and 3rd Mate got the job for our troubles at the next "ships trials".....third or fourth set of trials as the engine room had 6 foot of water after first trials.....anyway the three of us used the local DF station - clearly observed as it was the orange shed pointed out by the local pilot. We noted the readings and next morning set about calculating the curve.....it was a perfect sine wave, just like radio college. Needless to say no-one believed us and we had to re-do the bloody thing again - with the same results and same results from the Mate and Old man that we'd somehow flogged the results.

We then left it to the Mate and Old man and they got the same results.....must say the three of us doing it the first and second time never believed the results either until the Old man and Mate did the correction chart also.

Happy Daze!

MM²
24th March 2008, 16:46
This thread has awakened my interest to the extent that I got my sextant down from the Attic. God knows when I last took it out of the box.
It's sort of OK.
Does anyone know where I can get the mirrors re-silvered? If that is the correct term?

ray bloomfield
26th March 2008, 18:17
Was keeping an eye on a ship that was approaching about three mile away and would have passed clear red to red when he altered course to Std putting the CPA at zero. I asked via Vhf what he intended to do and a Russian sounding voice said he had just altered course to put the next waypoint (GPS generated signal display) on his radar dead ahead. At the time we were going around the Noord Hinder 'roundabout' I ended up having to take a turn out of her to Std. A clear case of someone elses GPS telling them it overides the rules of the road...

ray bloomfield
26th March 2008, 18:24
Sorry, dont know wether I'm coming or going, he altered course to PORT not Std, he was coming from the Hook bound down channel and we were bound for the Schelde from the Humber. (one of the places that need damming and turned into a fresh water reservoir!!)

James_C
26th March 2008, 18:25
Ray,
A situation we're all facing on an increasingly regular basis. Red line merchants etc.
To go in the opposite direction, when in the Gulf of Aden in February heading Westbound for the Gates of Hell, I had what turned out to be an LNG tanker crossing on my starboard side. Got a decent echo on the radar at 20 miles and the cadet started plotting him with the ARPA at 18 miles. By the time he was at 16 miles the 'magic machine' was telling us he had a CPA of 1.5' which it maintained until he was past and clear. Being a clear night we sighted him visually at 16 miles and confirmed his aspect, then told the cadet to take a visual bearing as soon as practicable.
Seconds later he called me up (Eastern European voice) with the words "are you a train, do you run on rails, you not alter one degree for me".
By this point we were about 14 miles away and I checked our ARPA again still saying 1.5' and his bearing was opening. He then said "CPA is 1.5 mile because I alter course to make 1.5'.
He'd felt the need to take avoiding action instead of maintaining his course and speed when at a distance of SIXTEEN miles and then had the temerity to berate me for not altering early enough!
I quietly replied that I am not in the habit of altering course for vessels which I can't even see and then changed channel.
It makes you wonder right enough...

Steve Woodward
26th March 2008, 18:43
How did we manage before GPS - simple answer really, Very well!

James_C
26th March 2008, 18:47
Steve,
Wouldn't be a terrible hardship to cope without it these days would it?
Not having to programme/set up/coerce into working that b*****d box in the corner would make life much more pleasant, and would probably lead to a postponement of oncoming baldness and perhaps a few less wrinkles.
Just as long as whoever did away with GPS did the same with LORAN!
Don't get me wrong it's a convenient wee thing - but at times too convenient. After all, when it gets to the stage where there are just so many people out there who you can't even trust not to get into trouble whilst having a machine telling them where they are to within metres, well...

ray bloomfield
26th March 2008, 18:57
James_C
we aren't blessed with the wonders of ARPA, our trading area is normally the north sea and channel and sometimes when we alter course for one we get tangled up with another but I do find the use of the AIS CPA facility and the radar does help when used together to identify targets. (as well as eyes!) Rgds Ray

ray bloomfield
26th March 2008, 19:07
Awhile back I took the old 'Blackbird' to Nigeria and one day out of Bonny the Giro packed in and the magnetic compass was on top of the wheelhouse and was to say the least was in dire need of someTLC (card turned with the ship) We came back to Aabenra in Denmark on the GPS alone. Plotting a position on the chart every two hours and then altering course as required to keep us somewhere near the intended track.

Steve Woodward
26th March 2008, 21:37
James C - like many I enjoyed celestial nav and we always seemed to get where we were going - even if we were relying on a two day old set of DR's but would celestial nav cope in todays 'gotta have it this second' attitude.
I think not, we were a more relaxed bunch back then time wasnt the be-all and end all it is now, to be fair to modern day seafarers they have far more on their plates now than we ever had and need all the labour saving devices they can get.
I own a sextant - do I use it these days - not a hope, it hangs on the bulkhead at home, my we boatie has a fixed GPS that gives me a fix when I need it and if that fails or the batteries fail a portable set will also get me that fix. and if all that packs in or Uncle Sam turns it all off there's always DR to get you home.
Steve

John Cassels
26th March 2008, 21:47
How did we manage before GPS - simple answer really, Very well!


Steve , must respectfully disagree ( changed your ideas since yr post # 11).
We managed because we had to, there wasn't much choice !.

No one can convince me that two crossed position lines taken 3 hours apart ,
obtained by sextant on a bridge wing probably heaving all over the place and
very often against a dodgy horizon could be classed as very well.
Even the run up between morning and noon sights was a guesstimate.

In retrospect , I cannot now think of many more inaccurate methods of
position fixing than the morning and noon sun sights which was my reason
for starting the thread.

R893891
8th April 2008, 21:04
I never used GPS at sea, the closest I came to it was LORAN and the DECCA NAVIGATOR (in UK waters). If I had to return to sea tomorrow I'm afraid it would have to be my sextant, chronometer and Norries Tables. A radar set would be useful as would a depth sounder. This is all I've ever used to circumnavigate the planet (without incident), but I suppose I'm a museum piece!

ChasD
8th April 2008, 21:49
Never ceases to fascinate me watching some dippy young female in the bar on a cross-channel ferry, phoning her boyfriend from the middle of the Channel on something the size of five Woodbines. I used to have a room full of knobs, dials and twiddly-bits to do just that - puts me in my era!(Smoke)

sparkie2182
9th April 2008, 00:04
yes chasD.....

but could she repair it when it goes "T*ts Up" ?

:(

trotterdotpom
9th April 2008, 15:33
Who fixes the barmaid when she goes t*ts up? Sadly not me these days.

John T.

Dick S
9th April 2008, 19:37
Hi,
I have to agree with JC aboout the accurracey of what was basically a running fix with an estimated speed and no current allowed(mostly).AKA a Noon Position! I hate to admit it but I was always slightly relieved when we made a decent landfall!!

But does anyone remeber the TAMYA Navigational Computor with built in Nautical Almanac that could do stellar and star obs and course calculations in the programming. It was the size of a big calculator and came in wooden box, Paid £100 for one in a well known Liverpool Nautical shop(Sewells?) in the late 1970s. The almanac part was no good after 1999 if I remember rightly. I still have mine somewhere.

Dick

John Cassels
9th April 2008, 19:48
Dick , remember reading about the Tamya but have never seen one.

When do the crossing Ijmuiden-Newcastle next monday , will have my small
handheld GPS ready. Bit silly really but can't resist it.

Bill Davies
9th April 2008, 20:04
Having sailed with Japanese mates on dozens of occasions they were all masters of those Tamaya computers. I never encountered one who did not have one in his possession.

surfaceblow
9th April 2008, 21:37
A Second Mate left one on my desk when he left the ship with a note saying it did not work. After I removed the varnish from the electrical connections the calculator work fine. It stayed on my desk for three months until he came back from vacation. The next time I saw the calculator it was back on the chart table when the Second Mate was on watch. The Captain gave the Second Mate a hard time about being an (Hippy) Indian giver that I needed the calculator for my sail boat.