which sextant?

[ColinR]

I've decided to bite the bullet and do the Ocean Yachtmaster, now I need a sextant. I don't know much about them, can anyone advise me which are good ones to look out for, points I should be aware of etc? Are the plastic ones any good?

Many thanks for any advice.

Colin

 

[snowleopard]

Plastic ones do the job. The cheapest can be hard to use but they will get you home with a bit of practice. A top-of-the-range metal one will set you back many hundreds and is overkill unless you plan to do a lot of voyaging and want to leave the GPS switched off. I bought mine second hand from a retired merchant deck officer many years ago and have since had the mirror re-silvered. It is as good as new but seldom comes out of its box.

This link shows the 3 basic types available new.

Beware when buying on eBay or antique shops. Most of the stuff out there is no use for navigation. You see lots of replicas that don't work, some with no scales, certainly not calibrated etc. If it doesn't have a micrometer drum, walk away. You don't want to be messing with a vernier scale on a small boat!

 

[john_morris_uk]

Plastic ones can be ok but a nice brass one is better. I remember using a plastic sextant once in the med' and having to check the index error after every sight because it would drift in the heat of the sun. (I know that you are supposed to check the error regularly, but the best sextants tend to have repeatable errors that don't alter from day to day.)

I happen to have a surplus plastic sextant which I was about to advertise. Otherwise look on e-bay? Just make sure that you don't buy an ornamental type 'display only' sextant. One like this might be ok: http://cgi.ebay.co.uk/Brass-Sextant...e_RL?hash=item2ea8151fbe&_trksid=p3286.c0.m14 but there are lots about.

Just found another one which looks a bargain at the current price! http://cgi.ebay.co.uk/RARE-CASSENS-...in_0?hash=item1e5899f1d3&_trksid=p3286.c0.m14

If you live a long way from the sea, I have heard that a wanted advert in a local paper might find one lying in someones loft that you can buy at a reasonable price.

There are some very simple basic checks that you can do to determine perpendicularity of the mirrors and frame etc which will tell you whether it is any good.

 

[BelleSerene]

An alternative to the better of these reasonably priced ones - better quality at the same price - is to get a second hand one from a place that knows what they're talking about. Talk to Mr Robinson of Robinsons of Hamble (http://www.compassadjuster.co.uk/contact.htm) if you're in that area. He has a good line in second-hand Soviet ones as well as some decent second-hand German ones. Otherwise, the Astra III in a previous poster's link is more than good enough for the job, and indeed the better of the two plastic ones is (certainly for low use in temperate climates).

Remember too that if you just want to 'do the Ocean Yachtmaster' (do you mean learn the theory or actually take yourself on a 600nm qualifying passage, do the exam and get the certificate?) then any plastic job is going to serve you fine: if your plot is wrong by a few miles because the thing's warped, what does it matter?

Avoid any sextant that you can't put back in its box with the dial at its correct point on the scale. Some of the worse ones will only fit with the micrometer returned to around zero, which means in practice that you either have to store it temporarily outside its box (risks damage) or have to note its reading before returning it (inconvenient). Again, Robinsons would sort you out.

 

[anniebray]

Another vote for the Astra 111B. This sextant is made from alloy in China for an American firm called Celestaire. I bought mine mailorder from Blue Water Supplies in Guernsey where of course VAT is not charged.

 

[sarabande]

I agree with SL and JM, except to say that eBay does produce some winners from time to time.

I won a really excellent and clean Freiberger (E German) one about three years ago for £75.

A plastic one is fine for practice and will give acceptable position line and angles off, but a metal frame one has more stability in the hand (inertia when boat is rolling) and for errors from heat, etc.

 

[bilbobaggins]

Plastic ones do the job. The cheapest can be hard to use but they will get you home with a bit of practice.

There are lots of plastic sextants doing the rounds of this forum. One well-known motoring forumeer acquired one to find his way back north to Alba, but hasn't been heard of since. P'rhaps 'cos the venerable Davis Mk II 'sun gun' was calibrated for the latitude of Hampshire.....

The plastic jobs are quite a lot harder to use, and thus frequently give a less satisfactory result, than 'proper jobs'. Hence much of the frustration which causes many yotties to give up too soon.

The Cassens and Plath on eBay ( John Morris' post ) looks an exceptional buy, if safely acquired around that bid, even allowing for the postage from India. The same seller also has a fine-looking Tamaya, at around $450. If risk-averse, head down to the Hamble.....

While some of the 'how to do it' books are now quite helpful - viz. Cunliffe and Bartlett - nothing beats a skilled someone to show you how. That's a fast track to getting usable results.

Enjoi!

 

[VO5]

I have a Carl Zeiss lightweight model specially designed for yachtsmen, micrometer, fitted with light for night sights. I have had it for just under 20 years. I paid for it then about £300 VAT free. Worth every penny.

 

[bedouin]

The honest answer is that for Ocean YM and anything you are likely to need a plastic sextant is absolutely fine. I think you would have to be an expert user to get a significantly better result using a metal sextant than a plastic one on a typical Ocean YM qualifying passage.

However having said that, a "proper" brass sextant is a beautify piece of precision engineering that is a delight to handle and use.

 

[30boat]

As was said before the difference in ease of use between a plastic and a good metal sextant is considerable.I'd go for a proper tool.

 

[timbartlett]

If you want to ocean navigate as cheaply as possible, buy a GPS.
If you are navigating for pleasure and interest, buy a metal sextant.
The price difference between a usable plastic one and a usable metal one seems to be getting narrower and narrower -- and the metal ones are stronger, more rigid (especially in warm weather), have better optics, and are easier to read.
And you can hand it on as family heirloom when you've finished with it.
Astra 3C's are fine. For yacht use, I'd suggest an all-view horizon glass rather than a half-silvered one.

 

[chart5011]

If you go for plastic avoid the cheapest Ebbco and go for the Special (slightly better optics and easier to read scale) all Ebbco's are hard to put properly into box. If still plastic but happy to pay more go for a Davis mark 15 for normal use or mark 25 for very cold climes.

Of the metal sextants I am very happy with my Zeiss Drum (now called Freiberger).

 

[Skylark]

The very fact that you'd like to do the YMO course (and qualifying passage) suggests that only a real sextant will do for you!

A real one is a joy to own, IMHO.

A plastic one will always be a plastic one, enough said.

There is already a lot of good advice in this thread.

I bought one from e-bay several years ago. Patience is difinitely a virtue. It took many months to find one, at an affordable price, but my tenacity utimately paid off.

I bought a nearly new Cassen Plath for a couple of hundred pounds. It has good provenance and I saved many hundreds more.

By all means buy a plastic one to play with while you're searching out your bargain.

There is another alternative.....just buy a new one!

 

[Deleted member 36384]

Indian Supplied Sextant Was Disappointing

........... The Cassens and Plath on eBay ( John Morris' post ) looks an exceptional buy, if safely acquired around that bid, even allowing for the postage from India........

Beware the Indian ones. I purchased one from the a colleague who was working in India, some place where all this marine stuff comes from (loads of marine hardware shops and markets), near where they scrap ships. It was a good quality sextant but no use for navigating with. The lead screw was damaged, mirrors squint and a calibration certificate obviously typed up on a word processor; basically shoddy and worn out! I paid £150 quid.

Indian companies make very good replicas as well - in fact they make good replicas of anything - but not good enough to use, just to look at.

I would buy from a UK place where you can see what you are getting.

I didn't look at the eBay links so you could get a bargain - but my advice is stick to local suppliers.

 

[bilbobaggins]

There you have it! The 'Big Hairy Beastie's completely right, as usual!

( I would say that, 'cos he's bigger than me... )

Nevertheless, there's another way to look at it. The Navstar/GPS system is just man-made astro - making fixes out of two, three or more circular position lines. The 'Murricain electric stars' up there don't last that long - half the bleedin' things are knackered now after only 15 years. As for the twee wee receivers, I've got four. Again, maybe half of them are working....

Now, the original, genuine, 'does what it says on the tin' stars 'n planets. They've been working away up there for us, stuck onto the inside of the Celestial Sphere, without a day's 'downtime, off-line for maintenance or obscure reported unreliability for yonks. Millions of yonks, actually. And they'll be there, insh'allah, long after thee 'n me have gone. Reliable or what?

Andanotherthing! Your genuine-beduine Zeiss, Tamaya or Plath 'sun gun' will, properly looked after as the precision optical instrument it is, be a cherished family heirloom you can bequeath to your grandchildren. It'll be worth more than you paid for it. Even though the little rug-rats won't have a clue what to do with it!

Andanotherthingagain! When Apollo 13 went 'titzup' while heading for the moon, it was real astro they used to find their way back.

Can't say that about a Tom-Tom or Trimble....

No contest!

 

[Fascadale]

One of these days I too would like to learn how to use a sextant.

I have an old sextant: the certificate on the inside of the box lid, from The National Physical Laboratory , Teddington , says the sextant, Class A, was made by John Lilley and Sons of London and North Shields. It is dated 15 October 1929, almost 80 years ago.

There is a correction in pencil on the label,"y- +6degs", dated 15 May 1942.

I don't think this instrument has been used since 1945

Is it likely that it will still work and is it worth getting it checked over?

 

[bilbobaggins]

the certificate on the inside of the box lid, from The National Physical Laboratory , Teddington , says the sextant, Class A, was made by John Lilley and Sons of London and North Shields.

Is it likely that it will still work and is it worth getting it checked over?

Certainly, it's worth checking out.

Send me a few e-images by PM. I'll have a look for anything obviously wrong ( then I'll ask BHM.... )

If it hasn't been 'wracked', dropped/bent, the screw damaged or other expensive physical damage, it may just need recalibrating.

It's worth a try.

 

[VO5]

One of these days I too would like to learn how to use a sextant.

I have an old sextant: the certificate on the inside of the box lid, from The National Physical Laboratory , Teddington , says the sextant, Class A, was made by John Lilley and Sons of London and North Shields. It is dated 15 October 1929, almost 80 years ago.

There is a correction in pencil on the label,"y- +6degs", dated 15 May 1942.

I don't think this instrument has been used since 1945

Is it likely that it will still work and is it worth getting it checked over?

The most important thing is not to look at the sun EVER without the shades in place. I used to sail with a second mate who ignored this when he sailed as a cadet. The result was that he burnt his right cornea and had a black spot in the centre of his vision, a nasty little black dot that swung around when he moved his eyes. Be warned. This danger is not mentioned often but is very real and PERMANENT.

 

[fantasia7628]

This thread has prompted me to have a look in the proverbial attic, where there is a boxed sextant that was left to me by my Godfather and I cannot see myself ever learning to use it. It is a VEB Freiberger Drum Sextant which according to the label was made in 1976. Is this make any good and what sort of value might it have?

 

[Fascadale]

PM sent to Mr Baggins