Wristwatches suitable for sailing, celestial navigation, anc scuba diving

[NYSail]

If I wear a watch it’s my time expedition....

[SeanPatrick]

Originally Posted by Jammer

I read up on lunars and understand that with the very best possible technique and equipment, under the most favorable conditions, an experienced navigator can shoot lunars with an accuracy of +/- one minute. While interesting, I'd rather have a good wristwatch.

Actually, it's possible to determine the time to within about 7 seconds using lunars. (Or even better if you're lucky.) I've been closer than 7 seconds multiple times. However, those lunars were shot from my yard, not from the pitching and rolling deck of a boat. It's probably more realistic to expect an average error of around 30 seconds.



But, what does that mean in terms of celestial navigation? Well, an error in time of 4 seconds is equal to an error in longitude of 1 minute. That means that even if you are off by 30 seconds of time, your longitude will be off by 7.5 NM*. That's good enough to get you within sight of land, where you can switch to coastal navigation techniques and is certainly good enough for the open ocean.


Don't get me wrong, though: I have a passion for precise watches. I currently wear a Bulova Precisionist which has a very constant rate of +0.2 seconds per day. Also, celestial navigation is a great way to pass the time and good for cross checking GPS and other forms of navigation. But, as has been said many times over at NavList (welcome, by the way), the best backup for a GPS is another GPS - or two or three.



*...at the Equator - even less at higher latitudes.

[PILOT P]

Rolex submariner - its a chronometer- its water ‘proof’ and they are virtually indestructible
Ive worn mine everyday for 30years in all sorts of ocean conditions above and below the surface
They keep excellent time and dont need batteries
They are expensive but you only buy one
You can also get them second hand from Bobs watches or other resellers at a reasonable price

[Alita49DS]

Originally Posted by PILOT P

Rolex submariner - its a chronometer- its water ‘proof’ and they are virtually indestructible
Ive worn mine everyday for 30years in all sorts of ocean conditions above and below the surface
They keep excellent time and dont need batteries
They are expensive but you only buy one
You can also get them second hand from Bobs watches or other resellers at a reasonable price

You only buy one. At a massively inflated price. You only need to spend a fortune to get it serviced every few years. You can never be confident if it is telling the time accurately. Which is what this thread is all about.

Accuracy relates largely to Hertz. Frequency per second. A mechanical watch is 4 or 5. A quartz watch is generally 32,768. So probably a greater difference between your jewellery Rolex and a grandfather clock.

There are many articles on the subject. This is one: https://quillandpad.com/2016/09/03/m...ncy-movements/

The article I liked best explaining it all was a brave one on the Financial Times watch supplement a few years ago exploding the cant about Swiss watches.

I did a case once about a Rolex and had cause to work backwards to how little the thing cost ex works. There was over 100% mark up at every one of the turns in the chain.

So by all means carry on enjoying the jewellery but for the time perhaps look at the clock on your chart plotter?

[Cheoy Lee 41]

I have a Casio “GULF Master" Solar Powered G-Shock - The Benefits.

It has dual time, and usual watch functions, stop watch, alarm, count down time, lap timer etc

1 No battery to worry about so never runs out I have had for 6 years
2 Precise time, every time, every day. Takes world wide radio time checks at least twice a day. Ideal for celestial Navigation
3 Depth limit 100 meters [300+ feet]
4 Shows barometric tendency
5 Shows Tide Cycle & Moon phases
6 Indicates Direction
7 Altemeter

heres the link:https://www.gshock.com/watches/master-of-g/gwn1000b-1b

[PILOT P]

And their are those that want one and can’t afford it!
Ive been a ships captain and marine pilot for a large period of my life so precision navigation based on precision time is paramount
He in lies the lesson - if its got batteries it will fail

[DaddaTony]

Check out the Rip Curl range surf and tide.

[Sindbaad]

Originally Posted by ranger42c

Casio G-Shock. Daily "atomic" updates.

-Chris

Cassio G. Solar charging; Radio Controlled, compass; pressure. Price under$100. Have had it for three years. No glitch.
Recommend.,

[a64pilot]

Originally Posted by Jammer

Change comes slowly to the tech diving community.


Generally, the tech diving community is moving to rebreathers, which pose their own peculiar problems for integration with dive computers.


There are a handful of tech divers who embrace air-integrated computers in some way, for example, for bottom gas and maybe a stage, but not for deco.


The prevailing theory of SPG failure in tech diving is that if you have a failure of any SPG (AI or not), you turn the dive, and how much gas you have left no longer matters because it will not affect your decision making.

Today’s news story about divers discovering a new species of fish, but not seeing the six gill shark. Screen shot is of a Shearwater Predator which can connect to a rebreather, you’ll see the reading of the three O2 cells, depth, mix, ceiling next stop bottom time etc.
I was going to a RB myself but didn’t cause if you research them, there are actually quite a large number of unexplained deaths or extremely experienced, very professional divers.

[a64pilot]

Same news article. They are on a RB, looks like a Meg. However with a RB you still have to carry all the required bailout bases, in this case three. A bottom gas, travel gas and deco.
The other two bottles on his back are of course RB gas, O2 and his dilutant gas.