Vintage Military Watch: What is the "Mark 11" watch adopted by the Royal Air Force?

There are probably very few people who will ever hear or even say the words "Mark 11" in their lifetime.
On the other hand, if you have heard or spoken this before, you are already an expert on vintage military watches.

So, today's topic is, what is Mark 11?

I would like to talk about this.

To watch the video, click here↓

Divided into five parts

1. What is Mark 11?
2. Specifications required for the Mark 11 3. Differences in design between IWC and Jaeger-LeCoultre 4. Various variations 5. Differences in watches issued to the British Commonwealth

It is as follows.

What is Mark 11?

IWC, Jaeger-LeCoultre Mark 11 Watches

First of all, what is Mark 11?

I'll be talking about this later, but it will take me back to before the development of the Mark XI.

Although World War I was over, the watches used during that war proved to play an important role in wartime.

This led to a demand for more accurate and durable watches.

Then the outbreak of World War II led to the creation of the Dirty Dozen.

Earlier I talked about the Dirty Dozen, which was a watch that was used by the Army during World War II and began to be used in 1944. It was issued by 12 different brands.

For more details on this, please check out this Dirty Dozen video.

Two years later, around 1946, watches began to be made exclusively for the Air Force, but while the Army was issued watches from 12 brands, the Air Force only received watches from two brands.

In short, the Mark 11 is a watch that was supplied to the Royal Air Force by the British Ministry of Defence, who created new standards for the Air Force.

Therefore, from the 12 brands issued to the Army, the most reliable and proven top brand was selected.

・Specifications required for the Mark 11

So what are those two brands?

This was the main issue, but through London-based jeweller Goldsmiths & Silversmiths, a selection of manufacturers who could meet the strict specifications of Mark 11 was carried out.

And the brands that were chosen were IWC and Jaeger-LeCoultre.

The Mark 11 in service with the Royal Air Force Jaeger-LeCoultre and IWC

Since it was to be used by the Air Force, it was required to be more robust and precise than those used by the Army.

Mark 11 specs

Vintage military watch, Royal Air Force Mark 11 standard, mark11originalspecsa-p-112g-0815-1

-Matt black dial

- Highly visible Arabic numerals

- Fine minute scale in white

-Waterproof to 20 feet (approximately 6 meters)

-Magnetic resistant with soft iron inner case

- 36 hour power reserve

・Daily difference within -4 to +4 seconds

-Hacking functionality is included

-High-grade Swiss movement

・The second hand is a center second hand with high visibility

It is as follows.

An important point here is that unlike the Army, the Air Force mainly uses radio to communicate with its comrades.

Therefore, every time radio electromagnetic waves are sent or received, electromagnetic waves are emitted inside the cockpit.

These electromagnetic waves cause ordinary watches to become magnetized, reducing their accuracy.

This led to the need for antimagnetic wristwatches to prevent any deviations in the accuracy of the timepiece.

At this point, out of the 12 brands in the Dirty Dozen, the only ones that could achieve these specifications were IWC and Jaeger-LeCoultre.

By the way, here are the watches that IWC and Jaeger-LeCoultre delivered to the Dirty Dozen (Army)↓

Dirty Dozen Used by IWC and Jaeger-LeCoultre

This Mark 11 watch is used by the British military as well as by members of the Commonwealth of Nations.

・Royal Australian Air Force

New Zealand Air Force

South African Air Force

will also be provided.

By the way, South Africa is a colony, so rather than South Africans flying fighter jets, it's better to think of them as an air force stationed in South Africa.

The watches were distributed to each country by groups similar to what we now call the Five Eyes or Quad, and the same watches were distributed to countries that shared those values.

What IWC and Jaeger-LeCoultre Watches Have in Common

Most of the Dirty Dozen watches have a similar design, and the only differences that can be distinguished at a glance are the logo and size.

First, let's look at the similarities between the designs of the two companies, which were designed to meet those specifications.

One thing they all have in common is that the Broad Arrow mark is on the dial, case back, and movement.

Broad Arrow is a mark that looks like an upward arrow and means that the item is owned by the British Army (British Government).

In short, watches did not belong to individuals, but were strictly controlled and had their owners indicated.

Let's take a look at the back cover.

The Mark 11 was code controlled as 6B/346, which stands for "Aircraft Navigation Equipment" and "Accessories and Unit Maintenance Parts."

The numbers below indicate the year and serial number.

For example, this number is engraved as 1380/48.

IWC Mark 11 Engraving on the back

This means that the 48 at the end refers to the year 1948, and the 1380 at the front refers to the production number.

This is the major commonality between the two companies.

Here we take a look at the subtle differences between each brand.

What is the difference between IWC and Jaeger-LeCoultre watches?

Like the Dirty Dozen, the designs of the Mark 11 from both companies are almost the same, so at first glance it's hard to tell the difference, but if you look closely you'll notice subtle differences and you'll see that the designs are changing little by little.

The movement is different

Mark 11 Differences between IWC and Jaeger-LeCoultre movements

Use this movement!

Since there were no regulations in place, each company was able to equip its watches with movements that could demonstrate their capabilities even when used for military watches.

First of all, IWC is equipped with the Cal. 89, which is still famous among manual watches today.

Even back then, the movement was well-known for being reliable, robust and stable.

Jaeger-LeCoultre will be equipped with the 488/Sbr, which is chronometer grade and has a hacking function.

The back cover is made differently

Jaeger-LeCoultre IWC Mark 11 Case back construction comparison

The IWC is designed to accommodate six screw openers, while the Jaeger-LeCoultre has four.

Jaeger-LeCoultre IWC Mark 11 Comparison of edge and windshield

Also, since the Jaeger-LeCoultre movement is thicker, the watch is also slightly thicker than the IWC.

The IWC is flat from the edge to the crystal, and although the back cover has a step, it is relatively flat.

The Jaeger-LeCoultre model has a rounded impression from the edges to the windshield.

The back cover is also angled to accommodate the thick movement.

The number of pieces produced varies

In fact, there is a big difference in the numbers produced.

First, Jaeger-LeCoultre delivered approximately 2,950 pieces between 1948 and 1953.

On the other hand, IWC delivered approximately 8,000 pieces between 1948 and 1953.

There is a difference of more than double, but there is a reason for this.

First, the Jaeger-LeCoultre watch was not shock resistant enough.

IWC's early watches did not have earthquake-resistant devices, but they later began to produce watches equipped with them.

But Jaeger-LeCoultre couldn't cope with that.

The earthquake-resistant device is Incabloc.

Location of Incabloc

As a result, production was discontinued and the product fell out of use in the early 1960s.

By the way, IWC continued to produce the watch until the 1980s.

An interesting variation of Mark 11

From here, let's take a look at the subtle differences in design depending on the year of delivery.

"Maru T" and "T SWISS T"

Comparison of Mark 11 Maru T and T-SWISS-T

As explained in the Lemania video, radium was originally used as luminous material for watches, but as this emits radioactive material it was eventually replaced with the less radioactive tritium.

There are various patterns in this exchange process.

The first one is the usual round T-shirt version.

If there is a round T printed on the dial, it means that the radium has been replaced with tritium!

This is proof that...

The second is the "T SWISS T" printing at the 6 o'clock position.

IWC Mark 11 T SWISS T enlarged

The watches were delivered after the rules were decided to change the use of luminous paint to tritium, so there is no need to stamp a round T on the watch later; instead, "T SWISS T" will be printed under the luminous paint at the 6 o'clock position during the manufacturing process.

We've been using tritium since the beginning!

That is proof.

Differences in the luminous paint at the 12 o'clock position

Most patterns look like this, with a triangular piece of luminous paint at the 12 o'clock position.

IWC Mark 11 - Triangle luminous paint at 12 o'clock

However, when the Mark 11 was first made, it did not have the triangle but looked like this, with two dots sandwiching the luminous paint at the 12 o'clock position.

IWC Mark 11 White Twelve

It is called the "White Twelve" because of the presence of the number 12, which does not actually exist.

You can't see them unless you look closely, but it's fun to spot these differences.

Differences between Jaeger-LeCoultre hands

Jaeger-LeCoultre Mark 11 Cobra Needle

This is a Mark 11 delivered in the early days of Jaeger-LeCoultre, and as you can see here it has cobra hands rather than the pencil hands that we usually see.

Perhaps there was a request to replace it with a pencil needle because of poor visibility.

Subtle differences between the Mark 11s issued to each Federation country

The Mark 11 issued to the Commonwealth countries has subtle differences to those issued to the British Army.

This was probably done to ensure that Britain had strict control over how much to distribute to each country.

So let's actually take a look at the differences between them.

South African Air Force SAAF

IWC Mark 11 SAAF (South Africa Air Force)

As explained earlier, the Mark 11 was issued to the Air Force of South Africa, which was a British colony, and the engraving on it includes the initials SAAF (South African Air Force), which stands for "South Africa."

Royal Australian Air Force G6B

Jaeger-LeCoultre Australian Air Force G6B/346 RAAF

A "G" is added before "6B" to make it G6B.

RA Broad Arrow AF (RAAF) is an abbreviation for "Royal Australian Air Force", meaning that the watches were issued to the Australian Air Force.

Hooked Seven

IWC Mark 11 Hooked Seven

This is an IWC Hooked Seven.

If you look at the number 7, you'll see that it is not a normal 7, but a hook-shaped 7.

Although very few, these individuals do exist.


So that's what I've been explaining about Mark 11 today.

The charm of antiques and vintage items is that even within a single model like this, there are subtle differences.

I can't help but think about how they must have made up for the missing parts with their inventory, or how they must have made parts to the previous specifications just before the instructions were given and then hastily made modifications.

This is a watch that was actually used in war scenes.

When you consider that the watch still works and can be used on an everyday basis, you can really see how sturdy and well-made it is.

Another fun thing about vintage watches is that by coming into contact with such items, you can come into contact with small pieces of history.