The broad arrow on the dial plus no case engravings doesn't compute. There was a civilian model with no outside case back engravings, but that would have a plain dial.
Do you have any photos? There are a lot of fake Mark 11s out there, and yours should be checked. Good photos would be a first step.
Thanks Michael. That was a quick reply!
I don't have photos - just a couple of pdf images created on a computer scanner. I could email these but they probably won't tell you much.
Tony
Hi again,
An email update with some details from the watch repairer:
"On the back of the case it read JWC Stainless steel.
The movement is Calabre C89 and the Movement number is 1162286.
The movement also had a old army sign inscribed into it"
Detailed pictures will have to wait till January. I will try to be patient!
Tony
The movement in your watch is a cal. 89 - 12lig S.C. Angl. from 1948, and is consistent with the non-INCA movements installed the first batch of Mark 11s acquired by the RAF in 1948. The "old military sign" you describe is probably the Broad Arrow, which ought to be there. Everything about the movement appears to be correct. The case back, however, should have the Broad Arrow, 6B/346 and xxx/48 engraved.
We will wait for images of the dial and of the case back, inside and outside, to better understand if you have a true Mark 11 or a "marriage." The lack of the correct engravings in the case back, and the dial, do not bode well for the former though.
Thanks for that.
I'm learning something new everyday...and now frantically googling "non-inca"
Would the dial have any engraved or stamped identifiers on the reverse or is the only dating evidence the layout and style of the painted lettering on the face?
I suggest we wait until January when we can see images, and then perhaps start a new topic on this.
That's encouraging, as only the military Mark 11 had "JWC" on the inner caseback, I believe. Maybe the outer engravings have been polished off?
Thanks everyone.
I'll follow Michaels cues and try to gather as much background info and decent images as I can.
This watch has been in the family for a while and there is a RAF connection but I'll have to quizz the oldies over Christmas about that.
Festive best wishes in the meantime.
Apologies for the quasi technical jargon. Non-INCA means not INCABLOC, or not shock proof. It was thought then that, by being INCABLOC the movement would be less accurate. Understandably, the RAF went for accuracy and the movements installed in the first 2,400 Mark 11s were not shock proof. That is is why they have the suffix Anglo, which I believe means Angleterre, to differentiate them from the other Cal 98 that were INCA.
The Cal 98s installed in the subsequent Mark 11s were INCABLOC. It appears that the RAF found that not being shock proof was a bigger problem than the potential loss in accuracy.
If the watch is an heirloom then it is more likely the engravings in the case back were polished off, and unlikely it will be a "marriage". I hope your elders will be able to tell you the story of that Mark 11, and that you share it with us.
Season's greetings.
Tony, you might be right, but I've never heard that. I'm not a real technical expert, but I can't see how having INCABLOC would adversely affect accuracy: on the contrary, a shock can allow a beat to be skipped, and INCABLOC would be beneficial for accuracy. And either way, the watch would meet UK specifications.
I always thought that these were cheap bulk sales --and the watches weren't the super-special timekeepers they are today...and in fact, that's one reason for poor water (and therefore dust) resistance.
But I could be wrong, and would be glad to learn more here.
That cleared the mists a little.
It also suggests that the reason the non-inca versions have survived is that it wasn't possible to convert them during their periodic refits, otherwise they presumably would have had the incabloc system fitted?
Referring to the observation from Ross, was there an official procedure for decommisioning watches and marking them or removing marks to show they were no longer crown property?
Incidentally it's the broken balance that the repair shop is currently fixing.
Michael. I also do not claim to be an expert, and do not have an opinion on how INCABLOC affects accuracy, if at all. I would also like to hear the opinion of an expert on this matter.
I did not make this up. I do not have this much imagination. :)
I read somewhere, and now I just can't remember where, that in the late 1940s, either the RAF, or IWC, or both, were of the opinion that INCABLOC had an adverse effect on accuracy - it was either INCABLOC, or the accuracy required and the RAF opted for accuracy. That is the reason why the first two batches of 1,200 Mark 11s each, ordered in 1948, had non-INCA movements, when all Cal 98s that were being manufactured already had that feature.
From what I understood, this turned out either not to be correct, or the loss of accuracy was negligible, and positively off-set by the longer time between repairs at Herstmonceaux, of the Mark 11s with cal 98 INCA.
I'll try to find the sources. Do not hold your breath, though. I am also on holiday. :)
I found a reference on the the negative effects of INCABLOC on accuracy, on page 51 of the book IWC Pilot's Watches by Ebner Verlag, on the article Ever Upwards, The Movements of IWC's Pilot's Watches: A History of Calibers by Gisbert L. Brunner, states "Although shock absorption had already been invented, W.W.W. had to make do without it because negative effects on the precision could't be completely prevented back then".
I realize Brunner is referring to the cal. 83 on the W.W.W. in 1945. I have not yet found the reference on RAF's choice to install the cal. 89 Anglo without shock absorption in the first two batches of Mark 11 in 1948.
In any event, at least one expert believes that in 1945 shock-proofing a movement had a negative effect on its accuracy.
Gents, great posting here and some good research! It makes for good reading...and again an education.