Thanks for posting, interesting article, I like the attention to detail with the boot laces!!
The story of the Omega watch in Dunkirk (10.06.2019)
https://timeandtidewatches.com/omega...m-hardy-story/
Thanks for posting, interesting article, I like the attention to detail with the boot laces!!
I enjoyed that, ta for posting.
F.T.F.A.
I may have missed it in the article, but, what does the second crown do? Turn the bezel?
Yes it does...see link for:
The Omega CK-2129 6B/159 ‘Weems’ which was produced for use during WWII by both navigators and pilots in the early days of the Battle of Britain. According to Omega, around 2000 of this version of the 6B/159 were ordered and issued, after it was decided that a rotating bezel would make calculations significantly easier during flights. The piece would features two crowns, the upper to adjust the time, while the lower is used to rotate the bezel. The decision to use a crown operated bezel was to reduce the likelihood of navigational mistakes being made, if the bezel were to be knocked out of place unknowingly.
...and more.
Edit Updates below. Almost certainly it does not turn the bezel.
Last edited by PickleB; 12th June 2019 at 13:33.
I understood that the second crown was a bezel lock rather than to rotate but you learn something new every day.
I think you're right. On many of the watches there is a locking piece under the screw down crown that makes this obvious. See this link for examples and also"The Omega, Zenith and Movado 6B 159 all used the same case, with a cam lever set into the case at 4 o'clock to lock the bezel" that appears to be used in this instance.
Interesting that Springbar article, thanks for posting it.
I also thought that the second crown was for locking the bezel.
I have never seen an external bezel being turned by a crown...
This is my Longines Weems. The second crown doesn't turn the bezel. You turn the bezel to set the seconds (because the movement doesn't hack) and the second crown locks it.
The case is 32mm. With the current trend towards big watches it always amuses me when small cased watches are described by some as "ladies watches". These were actually used by navigators in Lancaster bombers in WW2.
Last edited by trident-7; 17th June 2019 at 18:53.
Here's mine, the ones shown so far are the MKII versions, here's the Mark I, as used by Amy Johnson, so it is technically a Ladies watch!
They were, as explained earlier, a Heath Robinson solution to the problem of hacking for accurate navigation.
Last edited by M4tt; 22nd June 2019 at 09:53.
Can some one shed some light on how a rotating bezel helps with navigation? May be a daft question but I’m new to the watch world
Navigation is largely about the Speed / Time / Distance triangle - i.e. Speed = Distance / Time, or Distance = Speed x Time. If you know two of the three, you can work out the third.
When you're flying an aeroplane you usually have a known initial point - for example, the airfield from which you've departed, or on crossing the coast or some other landmark. If you know your speed, you can work out where you should be (your estimated position) from the elapsed time.
For example, you cross the coast at Dover at 1010. You're flying at 180 mph, so in 12 minutes (2/10th of an hour) you should have travelled 36 miles. Using multiples of 6 minutes (ie 1/10th of an hour) simplifies the calculation, but a slide rule can also help with the maths. Turn the bezel so that the 60 mark is at 10 minutes past the hour, and when the minute hand points to 12 minutes on the bezel, you'll be 36 miles further on. You don't necessarily need a bezel - you could just try to remember that 1010 plus 12 minutes is 1022 - but your head is also full of other stuff - so it makes't he pilot's job slightly easier.
Of course, you don't always know what speed over the ground you're flying at, since whilst you're going east at 180 mph, the airmass you're flying in may have moved west, or east or whatever. But, if you know that the channel is 24 miles wide at the point that you are crossing, and it takes you, say, 10 minutes to fly it, you know that your speed over the ground is 60/10 x 24 = 144mph. If your air speed indicator was showing, say, 180 mph at sea level, you'd know that you were facing a headwind of 36 mph. You can now adjust your expected timings and headings to allow for the known wind.
IIRC (and someone better qualified than may may be along to confirm this), RAF fast jet pilots tended before moving map displays and GPS to set their speed according to the scale of their maps, so that at a planned speed of, say, 420 knots, a distance on a 1:100,000 map of around 3.3 cm equates to around 15 seconds flying time. Why 3.3cm? Because that's the rough length of a gloved thumb, which means that knowing time elapsed since passing an initial landmark, you can estimate your current position in thumb lengths.
Good story. The Fifty Fathoms article is also a good read!