IWC Mark 11

The IWC mark XI 

It can be regarded as one of the most classic military watch, a model with a high-quality professional tool watch. MARK XI production started in 1948  and was in active service till about 1979 and it conformed to the British Ministry of Defence (Ministry of Defence, MoD) models of military regulations .

The IWC MARK XI have been adopted by the various British Commonwealth Air Force in England and Wales , Australia, New Zealand , South Africa and Canada , as well as Quantas Air 's crew . Each different dials and the back case marking represents different National Air Forces and year of deliveries. As such, there are many variations of IWC Mark XI.

Almost all of the MARK XI are orders from UK Ministry of Defence (MoD) or provincial air defense (AM) and orders were placed to London, Goldsmith & Silversmith Co., Ltd. (which was later renamed G & S to Garrards), which in turn ordered via and IWC and Jaeger-LeCoultre ( another watch factory that also produced Mark XI)

Gathering the information from a Taiwanese website on vintage watches, It is said that most early MARK XI had 36mm size , chromed case styles , but most visible, are 35mm in stainless steel case , stop second movements ( the majority ) . Then according to experts say , MARK XI has been tested as per British observatory level, not in Switzerland , but the NPL ( National Physical Laboratory ) in Kew , southwest London.

As such,  those dial with the Encircled T ( T have labeled the circle ) should be from the 1960s. The early 1950s , the British Ministry of Defense realized the radiation harm on the human body, so many of the early watch dials that have military radioactive luminous paint were recalled, some of the dials were destroyed, some fitted with newly re-create dials, while others will redone and painted on non-radioactive materials.

These reproduced by the UK Ministry of Defence or reconditioned dials were called the MoD Dial. Owing to the historical background factors , these dials were still considered " the original dial ." By collectors.

In IWC Mark XI, for example, from 1948 years to the beginning of 1950 those watches that were not recalled for replacement of dials  ( due to the special anti-magnetic soft iron -based material ) there is no King's Arrow and Circled T, and under 6 o'clock shall be marked T SWISS T. As MoD Dial, you generally have King's Arrow and Circled T, but only under the 6 o'clock SWISS. It should be noted , King's Arrow "/ l \" mark on the printed when some Swiss factory- printed , some British defense.

My first IWC Mark 11 is without the King's arrow and Circle T (as below)

As such, the IWC mark 11 was specifically manufactured to help RAF pilots to accurately pin-point their intended targets. RAF bombing raids throughout the Second World War had been notoriously inaccurate. An investigation conducted in 1941 revealed that only around a quarter of the number of bombers which claimed to have attacked their targets actually did so. Other investigations concluded that more than 95% of bombs missed their intended target by more than five miles. The cause of this was simply due to the lack of precise navigation.

Consequently, the old system of “dead reckoning” (determining your present position by projecting your course and speed from a known past position) was abandoned and the focus turned to astronavigation which required an extremely accurate timepiece.

The MoD put out requirements for a navigation timekeeping wristwatch, that would have a highly accurate movement with hack-device, an inner soft iron cage forming a shield to protect the movement from magnetic interference, a stainless steel waterproof case with a screwed ring in order to protect the crystal from sudden decrease of pressure, and a black dial with luminous hands.

Upon delivery, the Mk 11 was subjected to an exhaustive 44-day testing period for ‘Navigator Wrist Watches’. Each batch then had to be sent to the chronometer workshop of the Royal Greenwich observatory in Herstmonceux. All watches had to be sent there from active units for maintenance as well. These ‘fitness’ tests entailed a 14-day period rating in 5 positions and at least two temperatures, plus further tests for ensuring the antimagnetic and waterproof properties of each piece. After passing these tests, each watch marked for a 12 month interval were the tests had to be run again. The Mark 11 was originally reserved for use only by navigators while later on it was issued to pilots as well.

The Mk11 was introduced into the RAF and the FAA (Fleet Air Arm) in 1949 and into the RAAF (Royal Australian Air Force) in 1950. At first IWC and Jaeger Le Coultre (JLC) produced these watches. However, having bought 2,000 Mk 11s from JLC in 1949 the RAF decided to buy only the IWC Mk 11 from 1949 to 1953, when the last RAF orders were placed. The last IWC Mk 11 was delivered to the RAF in 1953 although it was not officially decommissioned until 1981.