IWC Mark XI 'Hooked 7', 6B/346, Steel

This IWC Mark XI is from 1952 and retains all of its military case-back engravings. The dial features the British military broad arrow and the circled ‘T’, indicating that tritium was used for the luminous material. The original dial of the Mark XIs were lumed with radium, but sometime in the early 1960s these replaced by IWC with tritium as it was less radioactive and far safer. Many collectors do indeed prefer the look of the replaced ‘T’ dials compared to the radium ones.

In 1948, the RAF ordered two separate batches of Mark XIs, with the calibre 89 ‘anglo’ or ‘angleterre’, without ‘Incabloc’. The ‘anglo’ designation, helped to distinguish regular Cal. 89s (with Incabloc), from those without shock-protection. At the time, the RAF believed the Cal. 89 to be more accurate without shock-protection, thus sacrificing Incabloc in favour of the most precise method of timekeeping. Later models, (of which this is one), gained Incabloc shock protection as a practical development of the earlier watches.

Housed in a 36mm stainless steel case with fixed lugs, it has antimagnetic hands and an antimagnetic cage protecting the famous manual winding Cal. 89 movement, beating at 18,000 A/h. The IWC Mark XIs were renowned for their timekeeping accuracy as this was a fundamental specification required by the British Armed Forces. As a result, these watches were regulated in five positions and tested in temperatures ranging from -5 degrees to 46 degrees over a 44 day testing period in order to meet the required standards.

Mark XIs were made for BOAC (British Overseas Airline Corporation), the RAF (Royal Air Force), the Royal Australian Air Force as well as other air forces and for civilians as well. The collectibility of this timepiece is largely underpinned by its historical significance as IWC’s entire modern Pilot range was inspired by the very Mark XI. With pilot watches very much in demand today, due to its casual and utilitarian feel, this particular piece certainly fits the bill, especially with its wearable 36mm case and with both dial and case in exceptional unrestored condition.

Viewings can be arranged in Central London by appointment.

Closer look

Brand:	IWC
Model:	Mark XI Ref. 6B/346
Movement:	mechanical manual-winding Cal. 89
Functions:	time-only: hours, minutes, center seconds
Features:	unrestored tritium dial
Case:	36 mm stainless steel
Crystal:	plexiglass
Bracelet:	NATO strap
Year:	1952
Box & papers:	N/A

This vintage IWC Mark XI has an unrestored dial. The bezel and the case are lightly scratched, appropriate to the age of the watch. The watch is guaranteed for authenticity and comes with a two-year warranty from A Collected Man.