Derek Francis Pratt (9 May 1938 – 16 September 2009) was an English horologist and watchmaker. Regarded by many within the field as a highly accomplished 20th-century watchmaker, Pratt was particularly noted for his contributions to high-end timepieces produced under the Urban Jürgensen brand. Additionally, he gained recognition for his independent creations, including an oval watch in the style of Breguet and a reconstruction of John Harrison's H4 marine chronometer. His development of watches incorporating remontoires that act directly on the escapement, even within a tourbillon mechanism, is considered a significant technical achievement. Pratt's engine-turned (guilloché) dials are also recognized for their quality.

Early life Pratt, born in Orpington, England, developed an early interest in watchmaking. He was known by the nickname 'Ticker' during his childhood. He attended Beckenham Technical School, and began formal training in watch and clock technology in 1955 at the National College of Horology in London. At the same time, he held a student apprenticeship at S Smith and Sons (now known as Smiths Group) in Cricklewood, north London. The three-year training was intended to include the finishing and assembly of a pocket watch, but due to a slump in the British watch industry, the syllabus was abruptly changed, and the class was denied that experience. This change led to Pratt's early departure from the program.

The former director of Horology at the College and Pratt's tutor, Andrew Fell, hired him after he completed additional training in production engineering and tool design. Together, they worked on clocks inside black boxes used in aviation as well as micro-soldering devices for the then burgeoning field of microelectronics. It was this work that took Pratt to Switzerland, where he was to spend the rest of his life, and to embark on his career as a watchmaker.

Career

After his work at Andrew Fells's companies, A. & M. Fell Ltd. and Felmada, ended in the early 1960s, Pratt took jobs at small companies specializing in microelectronics. One of them was with Kulicke & Soffa, a semiconductor manufacturer. In 1972, Pratt established his own business, specializing in watch and clock restoration and development. His horological interests included Gothic iron clocks such as those by Erhard Liechti (de); he also repaired household clocks, and worked on intricate and singular pocket watches.

A commission to repair a watch for the Swiss entrepreneur and antique watch dealer Peter Baumberger led to friendship and a business partnership that spanned decades. Amidst the Quartz crisis in the Swiss watchmaking industry, Pratt saw an opportunity and pursued a different approach: he acquired those seemingly obsolete tools of the trade, expanding his workshop with lathes, milling and guilloché machines. His focus was on hand making watches from the smallest screw to the case, and continuing restoration work on antique pieces. These machines were crucial for the work Pratt was to do under the historic brand Urban Jürgensen, which had been purchased and revived by Peter Baumberger in the late 1970s. Pratt also did a lot of work by hand, with a piercing saw or turns.Pratt possessed a strong understanding of mechanical principles and focused on the refinement of horological escapements. He developed noteworthy but little known solutions.

He started crafting entirely handmade remontoir tourbillon pocket watches using hand tools and hand-operated machine tools. The remontoir, producing a constant force, was an equally constant theme in Pratt's work: he encountered it both in the aircraft clocks as well as John Harrison's famous H4 marine chronometer. Pratt achieved a configuration where the remontoir directly drove the escapement, even within a tourbillon.

Consulting and collaborations

The Urban Jürgensen years In 1979, Peter Baumberger bought the 18th century Danish brand Urban Jürgensen und Sønner (now known as Urban Jürgensen or UJS) and in 1982, he brought Pratt on board as a consultant and technical director. Pratt would remain in that role until 2005. The vintage watch collector and expert Helmut Crott (and subsequent owner of the brand), noted in 2011 that perhaps "only his association with Derek gave Peter the confidence to finalize the deal. Derek was almost certainly the key factor in the acquisition of UJS; his extraordinary skills were needed for the 90 historic movements to be finished, cased and sold." Pratt's involvement with Urban Jürgensen was pivotal to the brand's revival and success with collectors in the 1980s and 1990s.

These decades were Pratt's most productive period: he made a series of pocket watches, mostly under the Urban Jürgensen name. He called these watches 'remontoire-tourbillons'. They are described in an article titled "A Tourbillon indicating full seconds with carriage-mounted remontoire, twin barrels and up & down indicator" from July 1991. These watches marked the introduction of the Wankel-inspired Reuleaux triangle to operate the remontoir.

In 1981, Pratt embarked on combining the two inventions, thus creating what is now known as his "First series remontoire-tourbillon watches" [sic]. The three watches also feature Pratt's engine-turning (guilloché) skills. Guilloché dials often have different patterns in different regions with the hard-to-execute change hidden by a chapter ring. Pratt's precise execution enabled variations in the guilloché pattern without the need to hide the junction. In the nineteen nineties, Pratt made a further series of three watches, known as the "second series". Their mechanical principles are identical to those of the first series. These watches have a minimalist steel bridge replacing the back plate, which reveals the movement of the watch. Furthermore, in this series, the cam is made from synthetic ruby, rather than steel.

In addition to the pocket watches Pratt made under the Urban Jürgensen brand, he also completed a sizable number of unfinished pocket watches that had come with the sale of the brand. Pratt added complications, finished and cased them. He also produced many guilloché dials for USJ pocket watches and wristwatches.

Collaboration with George Daniels for Omega While working for the Urban Jürgensen brand, Pratt was developing other ideas, and in regular exchange with his close friend George Daniels.

The co-axial escapement was attributed solely to Daniels for many years. In the horological world, however, it is well known that Pratt played an important role in bringing this revolutionary invention to life. Not only did Pratt advise and discuss the mechanism for regulating the speed of clocks, he made the dual-purpose escape pinion for Daniels' escapement, using a spark erosion machine he had retained from his micro-engineering work. Daniels and Pratt spoke on the phone every Sunday morning for years, discussing what they were working on in great detail, with sketches exchanged by fax.

According to David Newman, former Chairman of the George Daniels Educational Trust, Pratt was Daniels' greatest horological friend, and a brilliant horologist. Daniels was among the contributors to "Remembering Derek", the Horological Journal's December 2009 issue containing Pratt's obituary. He wrote: "Derek's understanding of escapements was of great assistance to me. He immediately saw the benefit of the coaxial escapement and enthusiastically accompanied me in visiting factories to discuss its worth. He could speak French and Swiss German fluently, which was essential to our needs."

Pratt was a modest man. In the July 1999 issue of the Horological Journal, he happily gave Daniels full credit: "What a great time this is for British horology. All horologists should feel as proud and excited as I do about the launch of George Daniels' escapement in an Omega watch. The fact that Swatch Group have found the courage, not to mention the money, to put a new escapement into mid-market watches is wonderful news for mechanical horology. That this escapement is to succeed Mudge’s lever escapement (developed to its ultimate form by the Swiss) fills me with pride."

In a Horological Journal article from July 1991, Pratt started out by stating "It is very difficult to produce anything new in mechanical horology. Something is lacking however in most contemporary horology and that is innovation." Whilst Pratt was talking about his remontoir-tourbillons in that piece, arguably, the co-axial escapement represents another one of these rare innovations that came out of modern times, and in part, his hands (as noted above, he made the crucial dual-purpose escape pinion). Today, the co-axial escapement is central to the mechanical identity of any Omega watch, used in most of the mechanical watch models currently produced by Omega SA.

Daniels' tribute to Pratt ended with this note: "With Derek's passing we have all lost an important mechanical horologist of great experience and great knowledge, who was above all generous and congenial in his dealings with others. I have simply lost a brilliant horological friend and companion."

Wristwatch collaborations

Pratt loved solitude in the workshop, but cultivating friendships with fellow watch- and clockmakers was very important to him, too. In addition to the weekly calls with George Daniels, he had lively exchanges with peers in Switzerland, the UK and the US. He opened the doors to his workshop to countless students of horology and was interested in the next generation of watchmakers. He also frequently contributed articles for the Horological Journal and attended as many events hosted by the Worshipful Company of Clockmakers as possible. Pratt became a Freeman of the Worshipful Company of Clockmakers in 1979, and a Liveryman in 1982 and received its rarely awarded Tompion Gold Medal in 2006.

Pratt had wanted to make a wristwatch featuring the Reuleaux triangle remontoir mechanism for a long time. In 2008, already in quite poor health, Pratt shared this idea with Stewart Lesemann and Ron DeCorte, two American watchmakers. DeCorte was the driving force behind the project. Together, they envisioned a wristwatch with a movement that would house twin suspended barrels and a one-second remontoir. Small wristwatch movements make the application of a remontoir quite challenging. This challenge aligned with Pratt's interest in resolving complex mechanical problems.

As Lesemann was working on the first and second prototype of the Derek Pratt Remontoir d'Égalité, Luca Soprana expressed interest in the work. Pratt and Soprana first met some years earlier, when Soprana, an Italian watchmaker, had visited Pratt’s workshop as a WOSTEP student. Lesemann continued work on the watch after Pratt's passing, and in 2011, presented the third prototype at the Derek Pratt Memorial Seminar, hosted by the British Horological Institute.

In 2014, DeCorte brought in Tom Bales, an American entrepreneur and watch collector. Bales invested into the completion of the watch, which Soprana took on. Since then, a handful of Derek Pratt Remontoir d'Égalité watches have been produced under the Derek Pratt trademark. With these watches, Derek Pratt's legacy is carried forth by Luca Soprana.

Independent watchmaking

The Oval

In 1982, as the Quartz crisis hit the Swiss industry, Pratt focused on his true passion – mechanical watchmaking – and embarked on a new project, a pocket watch known as The Oval. Officially named the Detent Escapement Tourbillon with Remontoir in an oval case, it has been described as Pratt's magnum opus.

The Oval's movement incorporates a remontoire within a flying tourbillon (a combination which he invented), detent escapement, a central minute-wheel bridge, "flying" mainspring barrel, moon phase, power reserve and thermometer. The movement, visible through a hinged case back, is widely considered one of the greatest achievements in modern watchmaking.