Just as “military chic” appeals to civilians in the form of bare-bones Land Rovers, cargo trousers and navy pea coats, military diving watches have a distinct cachet that attracts enthusiasts, and with a vengeance. Military watches for the infantry and aviator timepieces certainly have their own sorts of “cool”, but among the most coveted of all the timepieces issued to servicemen are the watches designated for navy scuba divers, frogmen, saboteurs, SEALs, and sailors.

In any list of the most furiously sought-after pieces are the original Blancpain Fifty Fathoms, all of the pre-1990s navies-only Panerais, IWC’s Porsche-designed Bund diving watches and other limited-production models that were unequivocally developed for the military without consideration for commercial or civilian purposes. These are the most “pure” of the models in the genre, but equally desirable are civilian watches that were altered for the world’s navies.

This second category actually accounts for a greater number of watches because most forces did not commission all-new-from-the-ground-up timepieces. It has been simpler and more sensible to order slightly modified versions of civilian watches. The roster is as impressive as the list of dedicated diving watches, for it includes Rolex’s “Milsubs”, assorted Zodiac SeaWolf variants, Eternas, Longines, Tudors and Omegas.

The key to the appeal of either type of military diving watch is the knowledge that all diving watches were designed solely for functionality, but the ones good enough for the services are somehow tougher. In either case, whether a bespoke design for a specific navy or a modification of a “street” watch, their undiluted purposefulness creates its own aesthetic.

1) Panerai

Panerais may now be the mandatory attire of macho movie heroes like Jason Statham, following the leads of Sylvester Stallone and Arnold Schwarzenegger, but their history is as genuine and authentic as it gets. “Real” Panerais were manually wound, with only hour and minute hands, starting with the Radiomir in its cushion case, and evolving into the readily identifiable Luminor with the patented clamp over the crown. Their users were professionals who regarded their Panerais as tools.

As a starting point, the original 47mm Radiomirs created in the 1930s, with “onion” crown and without a clamping system, fitted with “wire” strap holders, are for many the definitive Panerais. These featured Rolex and later Angelus pocket watch movements. Their size was borne of necessity, both to house the large movements, in massive and robust cases, while allowing space for bigger, and therefore more highly legible dials. They are the most “authentic” of all the currently available models.

Unbeknownst to the originators, they created a design language that would dominate men’s watches by the end of the 20th century, because Panerai is as responsible as any brand for establishing the popularity of men’s watches more than 40mm in diameter.

Panerais evolved, as do all military diving watches, through usage in combat, formed by the needs of Italy’s crack underwater commandos. We are now able to buy production versions of watches that only existed as prototypes, such as the Mare Nostrum chronograph of 1943, so it is clear that Panerai’s designers never “settled” on a specific template. After the Second World War and well into the mid-1950s, Panerai released watches featuring the case style used for Luminors, with myriad refinements and detail changes.

These are the models that introduced one of Panerai’s most distinctive elements, the aforementioned patented flip-down crown lock. With the case redesign, the inconvenient wire strap attachments, which required straps to be stitched into place, were replaced with conventional lugs. Also produced during this period was the legendary Egiziano, or “Egyptian”, a massive 60mm beast that was reissued, not too long ago, in an exact-scale replica.

2) Blancpain — Fifty Fathoms

In 1952, two French naval officers, Commander Robert “Bob” Maloubier and Lieutenant Claude Riffaud, were instructed by the Ministry of Defense and the French Navy to set up an elite unit called “Les Nageurs de Combat”, or Combat Swimmers. Just as NASA could not find available watches that would meet the desired specification for space travel, so did the two French officers find commercial diving watch offerings to be falling short of their requirements.

They approached Blancpain-Rayville S.A., who came up with a design with rotating bezel, and which was waterproof to 50 fathoms, or 91.4 meters. The figure was chosen because, as of the early 1950s, that was considered to be a safety point for divers: it was equivalent to the maximum dive depth for a diver equipped with cylinders containing a mix of oxygen and nitrogen.

Thanks to a stainless steel screw-back case, Blancpain could ensure water resistance to 50 fathoms while an automatic movement reduced the need to use the winding stem, a weak point for most diving watches that was so admirably addressed by Rolex with its special crown. Its large luminous numerals and markers are now the norm on nearly all diving watches. The 12-hour marker on the unidirectional rotating epoxy bezel could be positioned opposite the minute hand before a dive, so the diver could keep track of elapsed time with a glance.

Despite the plethora of types, Blancpain’s Fifty Fathoms (and variants produced by Tornek-Rayville and Lip) is thought to have been issued in the high hundreds, produced in batches as commissioned. Between the launch year of 1953 and the 1980s, the Fifty Fathoms also appeared with straps or bracelets, with or without date and in sister models like the smaller Blancpain Aqua Lung. Ironically, given the importance of the bezel in the evolution of the diving watch, there are versions with unmarked bezels, as well as repositioned winders.

According to Blancpain, the Fifty Fathoms certainly earned its military status, having been used “on countless secret missions on behalf of their respective countries, including France, the United States, Israel and Germany”. Other variants that tempt collectors were supplied to Polish and Czech services, as well as special models for the US Navy SEALs underwater demolition teams.

3) Rolex Milsubs

Among the most desirable and confusing of all military diving watches, Rolex “Milsubs” were Submariners modified in a number of ways to better suit the rigors of military use. The two most obvious changes common to most are the replacement of the standard “Mercedes” hand with a large “dagger” type, while the spring bars and bracelet were removed, replaced with fixed bars and over/under waterproof military straps. The replacement of the bracelet with a strap prevented unwanted reflections, as did satin finishing of the case sides. Furthermore, a circled “T” indicated the use of tritium luminous substance.

Because official data is hard to come by, one must assemble the various bits of information gleaned from auction catalogs. It would seem that the majority of Milsubs were ref. 5513s (British Royal Navy) and ref. 5517s (British Royal Marines), although certain British special services were issued with Sea-Dwellers. Also crucial to ensuring authenticity of this most copied of watches are the service engravings on the casebacks defining the issue.

Rolex was never a major supplier to the world’s navies. Few other examples spring to mind, aside from the ultra-rare GMT-Master (ref. 1675) supplied to the United Arab Emirates’ Ministry of Defense in 1972, with a symbol on the dial indicating its purpose. While “Paul Newman” Daytonas are now the most valuable of Rolexes, for those who adore military diving watches, the Rolex Milsubs supplied to the Royal Navy is the one to own. Let the bidding start at £25,000 for a knackered ref. 5513. I like to think that my humble ref. 1680 is its little cousin.

4) IWC Bund Military Watches

One of the most exciting designed-for-the-services diving watches was issued in 1980 for the German Navy by IWC, which was then owned by VDO. Called the Ocean 2000, it was designed in co-operation with Alexander Porsche, who developed a truly modern case made entirely of titanium; it would signify the birth of the Porsche Design-Line of watches. Titanium’s function as a case material was in its infancy, and IWC was among the first to adapt it to horological use.

The name of the watch reveals that IWC was prepared to specify water resistance to 2,000m, a still-impressive figure. The German Navy specified both mechanical and quartz-powered versions, as well as models that were completely antimagnetic for divers dealing with underwater mines. So complex was the specification that it took IWC four years to produce the first examples. The resultant timepiece featured a nylon strap with Velcro attachment, rotating bezel with large triangular indicator, white hour hand and red minute hand, with a white sweep seconds hand.

Because of the variety of models — IWC Bund specialists believe there were seven distinct types — the watch represents a mini-theme of its own for collectors. The variants include the different movement calibers, type of luminous material, as well as whether or not they were antimagnetic. All of the watches met NATO standards, although no other NATO navies adopted them.

Knowing how the military Ocean 2000s differed from the commercial models is crucial knowledge for enthusiasts. The military version’s bezel was black instead of gray, the crystal was flat instead of domed, and the edges of the minute hand were red. The central seconds hand was completely white; the civilian Ocean 2000 had a red tip on the seconds hand. Naturally, there are variants to confuse us, but military markings on the back — though easy to fake — are the first giveaway.

Although issued for specific military naval operations, the details of which are still classified, a number have found their way into private hands. Or, should that be onto private wrists? As they were de-commissioned by the German Navy, the military divers, combat swimmers and minesweepers were offered the chance to buy the watches they wore during their missions when they were discharged. Apparently, others were sold to civilian dealers, just as countless military watches were sold to civilians in the 1950s from “overstocks”.