I want to learn how to navigate without GPS

I want to learn how to navigate without GPS. I've searched the forum and found that plastic sextants can be ok. Which brands are ok? How much more is it for a real metal one? What's the difference in weight?

What's a good book to learn from? Are there detailed web sites?

I'll be on land until next spring, then I'll just be in Lake Champlain. But I think it'd be cool to know how, and it might even save my butt someday.

It'd also be cool if I could learn how to tell how far away peaks of mountains are.

 

Vermonter,

Plastic sextants need adjusted (index error) with almost every use.

A good metal sextant will go from $800-2000 US. Remember you will also need a Good timepiece. The shortwave time signal is handy for checking rate of error.

I learned Celestial Nav at a school but we used Florida Marine Institutes text. It is a simple "cook book" method.

If you know the hieght of a mountain & your elevation, by taking a sextant sight and obtaining the vertical angle, you can figure the height out. Simple trigonometry. I think Duttons or Bowditch have a chart for this.

Bowditch and Duttons both deal extensively with celestial nav but may be to heavy duty for a new student. I've seen a number of simpler books available but cannot vouch for them. Check out International Marine Publishers. They probably have a website.

Welcome to the forum & have fun learning to shoot the Sun & stars (Moon & planets too).

Tim

 

I started this thread awhile ago, yours is a good idea , it can be very rewardinghttp://www.boatdesign.net/forums/showthread.php?t=17851

 

I saw that thread but it didn't mention any specific models or brands of sextants that are good.

Is this one any good? http://celestaire.com/catalog/Marine_Sextants/Astra_IIIB/

Any other sources? Everything boat-related usually costs twice as much as it should. I'm hoping the increased competition online will bring prices down.

 

I think those sextants are made in China. They are probably the best price you will find for a metal sextant.

C Plath sextants are probably what most would consider the industry standard. Last I looked thier most popular model went for approx. $1500.

Tim

 

Yikes, maybe I should just learn with a plastic one, and save getting a nice metal one for when I'm going to actually need it.

For $1500 I could get 15 backup GPS units ;-) but that wouldn't help if the system was down.

 

Other than Sextant and GPS

I too am concern if gps system goes down, what about loran?
I used to navigate by dead reckoning and a compass. I actually traveled to a few place (short distances) in Carribean this way before GPS. I never thought much about it but with all these crazy countries capable of orbital rockets and Nukes, it doesnt take much to knock GPS out for good.

What else is there?

 

Ok I see, well this is mine and they were VERY popular, made in the GDR, BY freiberger prazisionsmeckanic, in 1977, they are probably still made and they are very good,

 

been around the world this one, and not on a plane either

 

Nice instrument Lazeyjack. GDR as in former East Germany? I knew someone over there made fine sextants but if I can't pronounce it I don't remember it.

Googled "sextants" earlier and saw C Plath might not be making thier classic models anymore. That would be a shame.

I used to have a ex-Royal navy Heath sextant. Sort of a mid-sized model. Got stolen from me.

Tim

 

Hey, this is a Boat Building forum, you know, do-it-yourself stuff.
OK, so I'm not suggesting you make your own sextent, but if you have a good engineering university close by why not see if you can find a student who will build you one as a project? They much prefer having a purpose to their projects.
It may be crap, but it may be surprisingly good, and should cost comparitively little?

Just an idea from a guy who doesn't like to spend any more than he has to, on anything.

 

mydauphin

I think nocking a GPS system would be very difficult.
I believe America is the only country that has one although I here that Europe is getting its own for obvious reasons.

So an enemy of America knocking out the GPS system would be silly as they wouldn't be able to use it either.

Poida

 

france is abt to launch as is china, get with the play Poida you ole bugger

 

you want to learn celestial, google up books Mary Bluet, simple easy methods
funny how all those expert old trawler and tug skippers vanished at the mentch of all this)

 

I aquired an ex Royal navy sextant off a man in the pub. Its a 'Heath' (what ever that is) Its sort of a mid size model.

He said he stole it of a bloke in America.