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Both sextant and transit advertised accurate
degree is 69.4 miles
One minute is 1.6 miles
20 second is 0.386 mile or 2,037 feet.

The sextant hand held on a rolling ship I wonder how close most could do on most days.
Does any one know how close with handheld Sextant in real life
?


Dave
Yes, if you are on land and your observations are correct and your time is correct and your charts are accurate and you have a good instruments you should be dead on. However, the whole purpose of that instrument is to let you know where you are when there are no landmarks available to the naked eye. But the limited knowledge I have on this subject is that you must be aware of the errors that can occur in your measurements and reference points. Accuracy is a matter of what care you put into those measurements and navigation techniques you have available to you. But you really do not appreciate these techniques until you have been truly lost. When the sky is the same color of the ground, the terrain is the same and you find footprints in the snow that are yours. And add to the fact you have no survival gear with you. I would have been very happy to know where I was with in a mile or so. So accuracy is relative. You need to know where you are so you can move to where you want to be. I am now the proud owner of about five compasses and one plastic sextant for use in a lifeboat!
 
Yes, if you are on land and your observations are correct and your time is correct and your charts are accurate and you have a good instruments you should be dead on. However, the whole purpose of that instrument is to let you know where you are when there are no landmarks available to the naked eye. But the limited knowledge I have on this subject is that you must be aware of the errors that can occur in your measurements and reference points. Accuracy is a matter of what care you put into those measurements and navigation techniques you have available to you. But you really do not appreciate these techniques until you have been truly lost. When the sky is the same color of the ground, the terrain is the same and you find footprints in the snow that are yours. And add to the fact you have no survival gear with you. I would have been very happy to know where I was with in a mile or so. So accuracy is relative. You need to know where you are so you can move to where you want to be. I am now the proud owner of about five compasses and one plastic sextant for use in a lifeboat!
When I was going into mountains . I take a CB and 35 feet of wire great long range. I do a compass too.

If going on water I take your advice and have more than one compass and a plastic sextant too.


Good advice for all.

Where live most think cellphone. It does not work in parts of mountains. So backers find hard way.

Most do not know part earth the magic compass does not work.
You need a radio compass, sun dial compass with watch or a gyro compass.

Dave
 
Having experienced storms in the Caribbean and North Atlantic on this ship I can guarantee we didn’t have any stabilization system.

The Satellite Communications Antennas did have servos, but they were controlled by the satellite signals not gyros (it was nigty watching the antennas move during swells, rough seas and turns).


While we had chronometers, they were backups to WWV.
World War FIVE?
 
World War FIVE?
That is what I am thinking too.
I have not heard of fiber under ocean replacement . Maybe long range radio. Remember over 40 years ago satellites was going to replace under telephone wire.

One thing about a major war they looking at any working engines and radio. That go news for owner hobbyist building engines.
If ever read in ww2 all hobbies was used in war effort. Like replacement part for all type of farm and car engines. Manufacturering electronic parts,. In France they small lathes like sb9 for making grease guns.I stay in hobby , It was large list.

Dave
 
There were a few that occurred last night while you were sleeping.
Life comes at you fast, you know (hypersonic speed and all that).
Try to keep up.

.

There things we do not know.
We get bits of information.
No we have analyze what really is and why.

Dave
 
That is what I am thinking too.
I have not heard of fiber under ocean replacement . Maybe long range radio. Remember over 40 years ago satellites was going to replace under telephone wire.

One thing about a major war they looking at any working engines and radio. That go news for owner hobbyist building engines.
If ever read in ww2 all hobbies was used in war effort. Like replacement part for all type of farm and car engines. Manufacturering electronic parts,. In France they small lathes like sb9 for making grease guns.I stay in hobby , It was large list.

Dave
Yes, I also read that in the USA small shops were NOT used for the war effort, apparently the corporations didn't try to contact them. However, I know that at least SOME of the small shops were used as I know of a small shop in Ellensburg, WA that had contracts with Boeing, which meant transporting over relatively krappy (by today's standard) roads, over a mountain, to Seattle area, probably a four hour drive in those days. now, it's only about 2.5 hours or less.

Even tho' these shops were not used for the war effort directly, I'm pretty sure they contributed mightily such as keeping agricultural machines working, and transportation, etc.

BTW,. there is a krappy tv show about zombies where the electric doesn't work, therefore modern engines wont work. But did they not know about diesel & steam? Krappy sci-fi.
 
Hi,
I work in merchant navy as engineer. We have sextant onboard. We have gyro compass and magnetic compass onboard too. It is duty of navigating officer to take noon sight everyday at noon to calculate for position. We also have GPS subscription for accurate position keeping.
Ships generally have a 2 stroke main engine which is really big. You can fit only one in most of the ships. Now there are some ships with 2 propellers driven by electric motors or smaller 4 stroke engines.
Some ships don't even have rudder, they have steerable propeller.

Regards
Nikhil
When working sundials the calculations was fun lot of but if noon or 6am or 6 pm fewer calculations need. Then the time year . Here is simple chart for correction.

Do not forget magic north correction This changes every year. (where at it about 0.5° each year.). So easy today with Excel.
Just try it some with a slide rule and paper

Dave

Tijdvereffening-equation_of_time-en.jpg
 
Its all coming back now.
My dad was a big ham radio operator back in the 60's, and I recall him tuning into WWV, but I had not heard that reference for a very long time.
Ham radio chat use to be a big deal.

.
In ww2 all Ham radios was stop until the end. I did of any help for war but never know
In California the ham cubs would with forests fires.

Dave
 
My Dad was still apprenticed at the outbreak of WW2. His workshop was taking all sorts of scrapped ICE engines and motors - and making generators for small cargo ships that needed electricity on board, for new fangled electrical stuff - like radios, etc. - so "coastal" ships could be used to replace ships being sunk in the Atlantic... - or become targets for German submarines themselves. Germany nearly defeated the British by sinking ships... a part of their siege tactics.
https://en.wikipedia.org/wiki/List_of_shipwrecks_in_June_1940
Often it was the Civil side of the War Effort that needed the small workshops , not just the National forces. - His first job, make that "seized and rusted" old motorcycle work so he could run errands (collecting and delivering parts) all over town. A good start to an apprenticeship! - The day after he finished his apprenticeship he joined the Navy... - and spent the war keeping ships' machinery working!
Lest we forget.
K2
 

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