In the context of the late 1970s and early 1980s when digital liquid crystal display (LCD) watches were becoming the popular choice of consumers, a memorandum was prepared considering the pros and cons of using digital display wristwatches for military use.
The memorandum was prepared by the Australian Defence Science and Technology Group (DSTG) in response to a request from the Royal Australian Air Force (RAAF) for an evaluation of an United States Air Force (USAF) report describing the results of a questionnaire to evaluate digital LCD watches for military use and a US Department of Defense military specification for digital wristwatches with liquid crystal displays (MIL-M- 87967).
The USAF evaluation of 500 prototype Timex Marathon digital LCD wristwatches over the period June 1978 to March 1979 and the subsequent report led to the development of mil spec MIL-M- 87967 released in December 1980. The result was the manufacture of the Stocker & Yale Military Type III, Class A Chronograph Digital LCD wristwatch. Extending this time-line a little further, does the Casio G-Shock which was introduced in April 1983 owe its origin to MIL-M- 87967?
USAF Evaluation of Digital LCD Watches (1979)
In 1977 the USAF recognised the need to adopt a standard commercial quartz crystal watch movement to replace the mechanical analogue navigator’s watch. The necessity for a replacement of the mechanical movements surfaced principally because of spiralling buy programs and the requirement for increased performance at reduced costs. The use of standard commercially available quartz movements in lieu of mechanical movements specifically built and qualified for the military was considered to be beneficial because of the inherent reliability, ruggedness, and accuracy of the quartz movement. This recognition was made in the context of the sudden saturation of the commercial market in 1976 and 1977 with digital wristwatches. As a first step toward adopting a standard commercial quartz crystal watch movement, the USAF undertook a project/study to investigate the possible application of small electronic timepieces to the various requirements within the military for wristwatches and stopwatches.
Objectives of the Study
The key objectives of the study were as follows:
1. determine the acceptance of digital display by military and civilian personnel who normally use government-issued mechanical analogue dial timepieces.
2. determine what features are essential and desired on a digital display electronic timepiece in relation to the individual’s job requirements.
3. determine what types and style of digital display wristwatches could be used in place of mechanical analogue styles.
4. develop a specification for navigation/submersible wristwatches.
5. develop a commercial item description for a simplified version of a digital watch which would meet the general timepiece requirements of GSA and DLA customers.
To meet the objectives of the study, the USAF procured 500 wristwatches. Of the 500 watches obtained, 50 were used in various laboratory hardware performance tests. The other 450 were distributed throughout the USAF, Army, Navy and other US government agencies that had personnel who were authorised to use a government issued watch.
450 testers were requested to respond to a questionnaire on the prototype wristwatches after one to four months of use (425 actually responded). Questions concerning five major areas of evaluation were asked: (1) evaluator’s background; (2) watch design and construction: (3) assessment of digital display; (4) mechanical problems; and (5) overall assessment. The questionnaires were analysed in detail, including detailed data recording and a computer statistical analysis of the responses.
The 500 wristwatches were prototypes. A standard Timex Marathon wristwatch was modified to include the following characteristics: black anodised case, plastic unisex strap, tritium backlight, 15 minute stopwatch, larger digit size, larger LCD viewing window, and enhanced water resistance to meet the requirements of mil specs MIL-W-46374B General Purpose Watch; and MIL-W-50717A Navigation and Submersible Watch. Unlike most commercial watches, the prototypes had a shutdown feature which allowed the watch to be turned off for long term storage, thereby eliminating any drain on the battery.
USAF: Assessment of the Study
According to the USAF report, the digital LCD watch was very favourably received by most of those who participated in the evaluation. The most favourable comments concerned the extremely precise accuracy of the watch, the clarity and easy visibility of the digits under varied lighting conditions, and the continuous readout function. The latter two features provided for hands-off operation and hence, the watch did not hinder normal aircrew operations. Another feature which was very favourably received was the stopwatch function. From the analysis of the evaluators’ responses and comments, it was strongly concluded that the digital dial quartz crystal style of watch could be integrated into the US Government inventory.
Prototype Wristwatches: Proposed Improvements / Modifications
The prototype watch under evaluation by the USAF, was however, not considered acceptable without modifications. The following paragraphs summarise USAF’s suggested improvements to the design and construction of the prototype watch.
Proposed Improvements: Watch Design and Construction
1. Reduce the thickness of the case to improve comfort.
2. Adapt the watch to accept a mil spec nylon web strap.
3. Improve the finish to prevent chipping of the black coating.
4. Mode buttons be positioned in the upper right and/or left-hand corners of the octagon-shaped case to avoid the accidental activation of the buttons.
5. adopt a ‘push-in’ setting button rather than the setting button being required to be rotated 180 degrees.
6. crystal be recessed or hardened to reduce scratching.
7. Shock and vibration features continue to be incorporated.
8. It was noted that the test watch was extremely accurate and surpassed military/federal specifications for timepieces.
9. A number of test watches were evaluated by Explosive Ordnance personnel against non-magnetic mil spec MIL-M-19595B which required a device to read less than five gamma at a distance of 4 1/2 inches. The watches were tested against this mil spec and were found to read greater than 200 gamma. To overcome this problem, it was suggested that the buckle, strap pins, and push buttons could be made of a non-magnetic material such as brass.
Proposed Improvements: Digital Display
1. It was noted that hours-minutes-seconds continuous display was required for navigation tasks, bombing time tolerances, underwater use, and a few other selected activities. But for most other activities, a display of continuous seconds was not a necessity.
2. A 24 hour display was considered essential for celestial navigation and was a desirable feature for many military activities due to the extensive use of Greenwich Mean Time.
3. While the stopwatch function was very favourably received, it was suggested that it be redesigned to provide for a longer time duration (i.e., one hour versus 15 minutes). It was further suggested that for divers, this function be increased to at least three hours. Additionally, it was recommended that the stopwatch function incorporate a memory circuit that would allow uninterrupted operation when changing between the stopwatch mode and the hours-minutes-seconds mode.
4. It was considered that the Tritium backlight may not be appropriate for ground combat operations or during escape and evasion attempts. It was desirable, however, for most other military activities.
An Australian Perspective: A Biased USAF Report?
The conclusions of the USAF study, in the opinion of DSTG, were somewhat over-generalised and biased in favour of digital wristwatches and appeared to discount important minority opinions.
The DSTG observed that the USAF analysis of results of a questionnaire survey of digital watches for military use was found to be somewhat biased in favour of digital LCD wristwatches and it appeared to unfairly discount a minority of respondents who found difficulty in accepting and/or using digital wristwatches. It was noted that digital time displays may be preferable to analogue time displays in particular tasks requiring an exact quantitative representation of time. Analogue displays, in contrast, have the added advantage of providing a visual cue (clock or watch hand position) of the relationship between different times, thus providing both quantitative and qualitative information.
As DSTG pointed out, the results of the questionnaire indicated that there was not unanimous agreement. For example, 15% of respondents experienced difficulty operating the buttons controlling the display functions, 44% found that the face crystal was easily scratched and an average of 9% of individuals rated the watch poorly on a visibility scale to estimate the clarity of the display image under different lighting conditions. Of greater importance was the acceptance of the digital format. Eleven per cent of the subjects indicated that they had difficulty in mentally adjusting to the digital display in calculating specific time in relation to the hour. It was stated that this difficulty was experienced both by navigators and pilots “especially during flight when time compression is more severe”.
MIL-M- 87967 (1980): Shortcomings Identified
The US specification for digital wristwatches (MIL-M- 87967, dated 12 December 1980) describes three classes of digital watches: Type I general purpose watch; Type II divers’ watch and; Type III aircrew/navigator/shallow water divers’ watch. Under the specification, watches differed with respect to the stopwatch duration, waterproof and shockproof limits, optional seconds readout, background lighting, and the number of numerals in the liquid crystal display.
In its report, the DSTG concluded that mil spec MIL-M- 87967 appeared to include most of the characteristics necessary to ensure compliance with military operational and safety requirements, although it was further noted that the specification allowed little scope for technological advances.
DSTG did however identify several perceived shortcomings of MIL-M- 87967 and recommended changes to the US mil spec should the specification be used in procurement of military digital watches in Australia. The proposed changes to MIL-M- 87967 were as follows:
1. The replacement of the battery should not degrade the waterproofing characteristics of the watch.
2. The dark viewing requirement in the US specification should be extended. The specification requires that the background luminance of either the incandescent, electroluminescent or self-luminous lighted background should allow the watch to be read in darkness by a person of 6/6 visual acuity at a minimum viewing distance of 12 inches (about 305 mm). The distance should be increased to about 600 mm to include operational situations in which it is inconvenient to move either the head or the arm in order to read the time, for example, a pilot flying with his left arm (with wristwatch) placed on the control wheel.
3. Any Australian legal restrictions or safety recommendations on the use of radioactive substances in self-luminous displays ought to be examined.
4. The International System of Units (SI) should be used in an Australian specification.
The DSTG also recommended that should an Australian Defence specification be developed for digital LCD watches, then the specification should require either a continuous self-luminous light source or an incandescent/electroluminescent lamp to backlight the time display for night viewing. According to DSTG, it would also be important that the display be lit more uniformly than was usually the case with a single incandescent source in one corner or at one of the short sides of the display.
To date, I have been unable to unearth evidence to indicate that a separate Australian military specification was prepared for digital LCD wristwatches.
Stocker & Yale Autoranging Chronograph Type III Class A Wristwatch
At least one type of wristwatch was manufactured in accordance with MIL-M- 87967, which is the Stocker & Yale Autoranging Chronograph Type III Class A Wristwatch (S&Y Chrono).
Photos: Ted (xpatUSA)
Photo: MWR Archives
MIL-M- 87967 describes the autoranging function as follows:
the chronograph mode watches shall accumulate time for a minimum of 3 hours and the autoranging feature shall reflect minutes in digit positions 1 and 2; seconds in digit positions 3 and 4; and tenths and hundredths of seconds in digit positions 5 and 6 during the first hour of operation. When autoranging after 1 hour elapsed time, the watch shall reflect hours in digit positions 1 and 2; minutes in digit positions 3 and 4 and seconds in digit positions 5 and 6.
However, under MIL-M- 87967 Type III watches were required to have a one hour stopwatch and a continuous second display (HH:MM:SS), six digits. With a one-hour stopwatch, and a six digit display, autoranging was not required, the display (MM:SS:TT) only needs to go to 59 minutes: 59 seconds: 99 tenth seconds.
The Type II was required to have a continuous second display, and because the stopwatch was required to go to 24 hours, it must autorange. For the first 59 minutes: 59 seconds: 99 tenth seconds the display was MM:SS:TT, as soon as it hits 1 hour, the display changes to HH:MM:SS.
The Type I only required a four position display (no seconds), and a one-hour stopwatch. For this, the display could be just HH:MM for time and MM:SS for the stopwatch.
So why is the “autoranging” feature included in the S&Y Autoranging Chronograph Type III Class A Wristwatch? The mil spec provides the minimum requirements, allowing scope for manufacturers to exceed those requirements if desired. This is precisely what S&Y appears to have done, because it was cheaper to standardise the module than differentiate between Type II and III watches.
MIL-M- 87967 Reviewed and Cancelled
A notice dated 15 December 1988 indicated that MIL-M- 87967 had been revised and determined to be valid for use in acquisition. A subsequent notice dated 15 May 1993 cancelled mil spec MIL-M- 87967 without replacement.
Beyond MIL-M- 87967
Despite the cancellation of MIL-M- 87967 in 1993 and as a testament to their usefulness, digital LCD wristwatches continued to be procured and issued by the US military. For example, Casio G-Shock DW5600E-IV (NSN 6645-01-356-5944), Casio G-Shock DW-6900-IV (NSN 6645-01-441-2762), Timex Ironman T5K478GP (NSN 6645-01-592-0538), Suuntos (NSN 6645-01-544-8874 and 6645-01-544-8873) and an analog/LCD combination – the Timex Expedition T83512 (NSN 6645-01-231-5540).
Watches such as the Casio G-Shock replaced the S&Y Chrono manufactured IAW MIL-W-87967, most likely earlier than 1993* when the specification was cancelled. Apart from the self-luminous feature, the ubiquitous G-Shock performed all the functions required under MIL-W-87967, however, the unit cost was lower than the cost of a MIL-W-87967 spec S&Y Chrono.
The G-Shock and Ironman were issued to student pilots in the USAF (and may still be today).
* Starting right after the first Iraqi war, there was a general house cleaning of specifications that were obsolete, not being used, or that had industry specifications that covered the same ground (these were really just reprints of the Mil-Specs, but maintained by ASTM, SAE and others).
In 1979 a quartz LCD watch with chronograph feature cost as low as US$50 to $100. In contrast, a mechanical chronograph with only a 30 minute cumulative timer cost about US$200. It is very easy to see why the USAF wished to place the LCD quartz watch in a good light when reporting on the results of the evaluation.
Examining the procurement records shows that analogue watches continued to be the first choice of many in the US military including in the USAF throughout the 1980s and 1990s. For example, around 38,000 Steel Marathon Navigators were purchased in a period of 10+ years. More recently, around 40,000 Plastic Marathon Navigators have been purchased in the past ten years.
Questions / Further Information
Does any MWRine have in his/her collection one of the 500 prototype Timex Marathon used in the study?
Would it be possible for a fellow MWRine to post the operating instructions for the S&Y Type III Class A?
Feel free to post any further information on the S&Y Type III Class A watches, including additional images.
Many Thanks Ted and Lysander
My sincere thanks to Ted (xpatUSA) for kindly allowing me to use his photographs taken of his S&Y chrono. I know that Ted is seeking replacement (backlight) tubes for his S&Y Chrono, can anybody assist?
Many thanks also to Lysander for continuing to be an invaluable source of information and in particular, providing technical advice relating to the S&Y Chrono and related mil specs. Lysander has undertaken extensive research on the procurement of digital LCD watches by the US military, which is best presented by him (hopefully as part of this thread).
In a sense it was a team effort, however, any mistakes/omissions are mine.
Best Regards, Ken