Chronosport UDT – a brief review by Elias

chrono 3

The first ChronoSport UDT (Universal Diving Timer) probably appeared in the mid 1970’s, and quickly gained a reputation for rugged reliability and precision. It was supposedly produced to meet military contract requirments, and was sold to the militaries of several countries. The earliest design, and I’ll call it Type I, had two pushers at 4 and 8. I’ve not had any luck restoring these early models. Neither ChronoSport, nor Breitling, the quartz movement supplier, were able to provide replacement movements.

The three dials pictured below, show from left to right how the design evolved.


chrono 2

The next generation, and I’ll call the Type II, appeared in late 70’s or early 80’s, and had the now familiar case design with 3 pushers at 2, 4, and 8. This is almost identical to the Breitling Pluton, which shares the same movement. Case diameter is approximately 42mm without crown, and approx 12mm thick. Lug size is 20.5mm. It has the heft, feel, and understated no nonsense look, of a tool watch. The screw-back case is rated to 20 ATM.

For the first several years, a baton dial was employed and I’ll call it The Type IIa. Later, and at the request of US military users, the Type IIb dial was introduced. It is essentially a US mil-spec dial, with the familiar inner 13-24 chapter, and adapted to the ChronoSport case. On the Type IIb dial, the ‘Sea Quartz’ over the 6, disappeared, and ‘UDT’, moved from under the ChronoSport logo, to above the 6 position.

chrono 3

This design was used until the early 90’s, when the Type IIc was introduced (not shown) with the disctinctive bezel incorporating a compass rose. If any MWRine can provide a scan of a UDT with the compass rose bezel, this review would be more complete in it’s coverage. Talking of bezels, the ChronoSport used several types of ratcheting uni-directional bezels, note the difference between the bezel of the stainless steel model below, and the black model above. Some employed a count-down bezel, and others used an elapsed time bezel, depending on intended use. These two types turn in different directions, and the 15 minute hash marks are on different sides. The watches were sold with Breitling signature crowns, but they come back from service with unsigned crowns. Service interval (battery life) is nominally three years. Towards the end of the battery life, the seconds hand starts to move with a jerky 3-second increment motion, warning the wearer that it’s time for a trip to the service center. My dealings with the service center have been pleasant, and smooth. In addition to a battery change, a trip to the service center involves ultrasonic cleaning, new gaskets and seals, a new screw-down crown and pushers, and 20 ATM water pressure testing.

The watch runs with impressive and incredible accuracy. The digital display, once synchronized with the analog hands, will maintain perfect synchronization, and accuracy between service intervals. You can watch both the analog and digital seconds tick away in perfect synch! These watches were issued by some Army and Air Force units, and possibly other US services, probably as a unit purchase. I’ve seen sevral examples engraved on the case back, using hand tools, in the time-honored supply sergeant style, showing unit property book markings. I have not seen any examples with factory enagraved government property and contract markings typical of US issue watches.

The issued watches came with US mil-spec 20mm black nylon straps, identical to those sold on MWR. Starting about mid-80s signed bracelets were available as an individual purchase item, and came in stainless steel, and black PVD. The black PVD bracelets were available in two styles, one of which incorporated a diver extension.

chrono 4

chrono 5

Below is the Type IIc w/ compass rose bezel:

chrono compass

Below is an example of the “Champagne” Chronosport UDT:


The Champagne UDT was also available with a black dial (at least with the earlier Type I models) – and was included in a Champagne series :


Champagne Ad-ict

An early Chronosport UDT (Universal Diving Timer) Ad:

Underwater dive timer

The following watch utilizes one of the rarer bezel types found on the Chronosport UDT – a countdown timer bezel:

jimrltimer( photo kindly provided by Jim C. of MWR )

The following photo is believed to be the last version that they marketed circa mid1990’s:

FS Black Chronosport UDT with box and papers-large

ChronoSport:Documentation of Procurement

According to Elias there has been some controversy over the ChronoSport’s watches and whether or not they were actually issued. I did a search for the NSN found on the back of one of Elias’s Chrono’s and came up with the following:

Procurement History : NSN 6645011878475
….Contract…………..Award Date…..NSN ……………….Qty….Unit Price ….CAGE – Company
DLA40089C1054….04/01/89….6645011878475….180….$ 367.50 ….64151 – CHRONOSPORT INC
DLA40086C1872….04/01/86….6645011878475….345….$ 192.50 ….64151 – CHRONOSPORT INC
DLA40085C1198….02/01/85….6645011878475….410….$ 192.50….64151 – CHRONOSPORT INC

Expensive for a Mil Watch. These also should be relatively rare with only 935 purchased (at least during that range of dates).

ChronoSport circa early 90’s. Later sales brochures (mid-late 90’s) from ChronoSport that I have saved, omit mention of the NSN, probably indicating it was no longer being procured.

I have not seen any watches with a factory engraved NSN, but I’ve seen some with unit property numbers engraved, and these were mostly the early Type I, or 2-pusher model.

Great piece of research, that IMHO proves provenance.

chrono paper

ChronoSport Service Center Contact info:

website (no longer shows ChronoSport watches for sale)

snail mail:
25 Van Zant Street
Norwalk, Conn 06855

Phone: (203)-899-1983 Bill Dyer
Fax: (203)-899-1985


Both following Companies carry needed spare parts and have the right expertise, skills and equipment to service and refurbish these watches:

25 Van Zant Street
Norwalk, Connecticut 06855

Horological Services
(Vintage Breitling Svc)
146 W. Philadelphia Ave
Boyertown, PA 19512-1430

Special thanks go to Tito and Ned for helping me in preparing this article. As always, anecdotes, comments, and additional scans are invited.

Review, photos, etc are the property of Elias – regular contributor on the Military Watch Resource..


Jordanian Chronosport UDT – Images and Info from Rafael T. (of MWR) …

The following Chronosport UDT is one of several hundred commissioned by His Majesty King Hussein I, to be presented as gifts to visting dignitaries (including General Norman Schwarzkopf).  In addition to the silver version, Jordan also commisioned a number of black PVD examples which were issued to  Jordan’s Secret Service and other elite units.  Chronoserve reportedly has a few of these dials in stock – but only as replacements for those watches which currently have them (water-damaged watches, for example).

Rafael one

Rafael two

Rafael three


Chronosport UDT Watch Product Test Report



The image and text are a little difficult to make out, therefore i’ve copied it for an easier read:

There has been much discussion about the advantages and disadvantages of traditional watches and digital watches over the last few years. Many divers favor the dial face and hands because it is easier to read at a glance. This can be important when a diver is under stress or experiencing narcosis. On the other hand, the advantages of the digital watch is its accuracy. The digital read-out gives an exact number rather than a general time.

Chronosport recently introduced a watch which combines the advantages of both types in a single unit. At first glance the Universal Diving Timer (UDT) appears to be an analog watch with the traditional face and hour/minute hands but a closer look reveals a small windo in the bottom half of the dial face ; in this window is an LCD (Liquid Crystal Display) digital read-out, in this case a watch within a watch.

The UDT is powered by a tiny quartz crystal and a battery which does not require winding. As with most Swiss-made quartz watches the accuracy of the UDT varies less than one minute per year. In addition to accuracy, quartz watches are less influenced by temperature, motion, friction and certain other factors than mainspring watches.

The UDT gives time with a dial face like most other watches. There is the ususal outside ratcheted bezel which allows a diver to keep track of bottom time. The hours and minutes are easily set by the crown found on the right side of the watch. What makes the UDT so different from other dive watches is the small window in the bottom half of the dial face. The LCD gives a continuous digital read-out of three separate time functions. The series of four digits are black with a silver background and can be read in the daylight or dim underwater light. Depending on the sequence in with the two buttons located on either side of the dial face are pushed, the LCD provides a stopwatch, a second time zone or seconds and date.

For a diver, the most important function of the digital read-out feature is the stopwatch mode. By pressing the button on the right side of the watch, the chronograph stopwatch starts the counting operation with minutes on the left and seconds on the right. When the lapsed time totals 59 minutes and 59 seconds, the stopwatch will automatically switch to hours and minutes and continue counting up to 24 hours. The stopwatch can also measure bottom time. Just push the button at the beginning of the dive and press it a second time when the ascent is begun. At the end of a decompression dive, a diver can easily keep track of bottom time with the digital read-out while keeping track of decompression time with the bezel or vise versa.

Another function of the read-out display is a second time zone capability or an alternate method of reading the time. By pushing both bottons in sequence, the watch will read military style time. In other words, if it was 2:00pm, the display would read 1400 hours. If you are traveling, a second time zone can be set independent of the dial face. For example, if your visting Hawaii, the dial could read Hawaiian time, but the read-out display could give you the time back home.

The last function of the digital read-out display is telling the passing seconds and the day of the month. The watch is equipped with a memory and the date need not be corrected, except during leap years.

The UDT watch has a military look and is in black-chromed case with a black dial and strap. The watch is slimmer than most dive watches because the electronic components are miniaturized. The quartz crystal is recessed below the level of the one-way ratcheted bezel to protect it from damage.

The UDT is guaranteed accurate to within one minute per year and the case is pressure-tested to 10 atmospheres or 330 feet. The watch is backed with a five year limited guarantee, and sells for $295. For more information see your local dive shop or write to: Chronosport Inc. 119 Rowayton Avenue, Rowayton Connecticut 06853″

The article metions : “is in black-chromed case” – here is some further information about this coating:

Black Chrome


Black Chrome is a semi hard, non-reflective, abrasion-resistant, heat and corrosion resistant coating (approximately .0002” thick). The Black Chrome finish can be rendered very lustruous for consumer decoarative applications; and clear coated for a functional use. The Black Chrome process has poor throwing power; and conforming anodes are necessary for coverage on intricate shapes. This coating is applied after heat treating and all mechanical operations are performed. 

The Black Chrome surface may be waxed or oiled to darken the surface. Coating provides limited corrosion protection, but added protection can be obtained by specifying underplate such as nickel or copper.

The coating color is a dull dark gray, approaching black; and becomes (black) pearl-like when polished. It shall approximate color plate 37038 of Fed. Std. No. 595. Steel parts with Rockwell hardness in excess of Rc 40 shall be stress relieved prior to plating by baking one hour or more at 300° F to 500° F and baked after plating 375 F°  ± 25 F° for 3 hours minimum for induced hydrogen embrittlement relief.

Applications include:
Plumbing fixtures; Firearms (over hard chrome); Laser usage components; Neuclear sighting gauges; light absorption components


Chronosport UDT Owner’s Manual and Warranty







This manual has kindly been provided by Elias  of MWR

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