Angelus U51 Diver Tourbillon

After wearing the Angelus U51 Diver Tourbillon for two weeks, Angus Davies discusses the model’s composition in detail and explains why he is smitten with this subaquatic leviathan.

Looking through the rain-soaked windows of my office, it is difficult to remember the warm sunny days of summer. However, it was only a few weeks ago that throngs of people were clad in t-shirts and shorts.

Some sun-loving motorists enjoy basking in the sun’s gaze while at the wheel of a stylish convertible. When driving slowly along congested roads, the UV rays tan anaemic flesh, engender an overall sense of well-being and provide a plethora of posing opportunities.

Once the traffic has dispersed and an open road comes into view, the driver’s right foot feels an overwhelming urge to squeeze the throttle. Within a few short moments, the car devours the horizon in a bout of accelerative abandon.

Sadly, the problem with many convertibles is that they are often modified family hatchbacks, lacking torsional rigidity and exhibiting a propensity to flex on twisting roads. As any purist will attest, for a convertible to be considered a thoroughbred it has to be designed as such from the outset.

Every force acting on the vehicle influences the behaviour of the car’s torso. Ideally, this should be considered at the design stage. A reinforced floorpan mitigates the chance of flex, while a rigid windscreen surround ameliorates so-called ‘scuttle shake’. Right from the conceptual phase, the finest convertibles are designed with torsional rigidity in mind in order to grant the ultimate driving experience.

Likewise, torsional rigidity is equally important in the esoteric domain of skeleton watches. Often a skeleton watch is based on a regular timepiece that has been subsequently openworked with a small handsaw blade. Experienced practitioners of this technique know not to remove material from areas near jewel beds and screws and avoid parts of the plate in close proximity to the gear wheels. Overall, the finest examples exhibit an almost transparent quality while still retaining a sufficient degree of stiffness.

However, today, an increasing number of watches are designed from the outset as openworked watches. This clean-sheet design approach ensures all loads are considered, rigidity is optimised and visual lightness is realised. The Angelus U51 Diver Tourbillon is an exemplar of this approach to skeleton watch design.

Recently, I wore this Angelus model for two weeks and appraised its composition at close quarters.

Dial side

Designing a skeleton watch presents an array of challenges. Setting aside said torsional rigidity, the composition of the dial should reveal those components which contribute to the overall aesthetic allure. However, this can lead to a significant problem. Sadly with some skeleton watches, the free disclosure of parts, which are usually hidden from view, can lead to a cluttered dialscape, impairing readability. Indeed, I have seen many openworked dials where the hands become lost in a sea of parts and bony sections of main plate. Having worn the Angelus U51 Diver Tourbillon I can attest that no such issues afflict this bold diver’s watch.

Angelus U51 Diver Tourbillon

The blue hour and minute hands incorporate white and orange inlays, respectively. Both hands are treated with Super-LumiNova, aiding legibility in restricted light. A small seconds display is positioned between 9 and 10 o’clock. If I am honest I seldom looked at this latter indication while the watch was in my temporary possession, but it does provide divers with a useful indication the movement is functioning.

A series of beam-type bridges span the dial area. These bridges emulate the rigid structures often used in motorsport. Moreover, they are made of titanium, hence mitigating the overall mass of the watch. While the aesthetic appearance of this timepiece is contemporary, Angelus has not eschewed traditional craftsmanship. For example, the tourbillon cage is mirror-polished and features chamfered and polished edges.

The setting mechanism has been relocated to the front of the watch and positioned between 3 and 4 o’clock. Setting the time provides a delightful dose of horological theatre. Indeed, Angelus should be applauded for going to the trouble of inverting the setting mechanism purely to heighten the visual allure of the dial area.

Three twin-arm beams support the tourbillon cage. These beams feature special screws with torque optimising heads. The tourbillon cage sits on a ball bearing instead of pivots in order to enhance stability. Lastly, the cage rotates 360° every minute.

One of my favourite parts of the movement, when viewed from the front, is the spring barrel and ratchet. The mainspring is shown in all its glory, allowing the wearer to easily see when the spring is relaxed or in a state of tension. The barrel is presented in an eye-catching six-spoke design that is employed on other areas of the movement, including the gear train. Not only is this six-spoke design attractive it also confers incredible rigidity.

Angelus U51 Diver Tourbillon

A unidirectional, internally adjustable bezel encircles the dial and is adorned with blue and orange hues. The bezel is adjusted with the upper crown, located on the right flank of the case. The bezel is marked with Arabic numerals and used to time decompression stops when diving. The first 20 minutes are marked in one-minute increments against an orange backdrop, while the remaining areas are depicted in blue and marked with Arabic numerals at five minute intervals. Another detail which I also like are the diagonal recesses found on the internal bezel scale. They mimic the design of the outer surface of the titanium bezel and imbue the watch with a sublime flourish of style.

The case

There is no escaping the leviathan-like scale of the Angelus U51 Diver Tourbillon. It is huge, measuring a substantial 45mm in diameter. However, it is constructed of Grade 5 titanium, mitigating mass. While this watch will prove too large for some aspiring wearers, I did not find its generous scale to be a problem. Indeed, the watch fitted comfortably on my wrist and at no stage felt cumbersome.

Angelus U51 Diver Tourbillon

On the right side of the case, the watch is endowed with two crowns, each nestling within suitable protectors. The upper crown adjusts the internal bezel, while the lower crown is used for time setting and winding the mainspring.

The Angelus U51 Diver Tourbillon is beautifully detailed. The lugs are slightly open-worked, the bezel features a becoming pattern and some areas of the case sparkle resplendently. The fitment of an exhibition case back allows light to flood through the movement, augmenting its prepossessing appearance. The watch is supplied on a blue rubber strap, paired with a titanium pin buckle. A helium valve is positioned at 9 o’clock.

The movement

The Angelus U51 Diver Tourbillon is equipped with the in-house, hand-wound Calibre A-310 movement. In some instances, the Swiss brand has inverted components in order to indulge the whims of horological voyeurs.

The balance is fitted with an index adjuster and has a frequency of 28,800 VpH (4Hz). The movement contains 23 jewels and the power reserve is a remarkable 120 hours.

Viewing the movement from the rear of the watch, six-spoke wheels and twin-spoke beams abound. This facet of the design proves both practical, mitigating flex, and attractive. Personally, I love the sun-burst decoration on the crown wheel (transmission wheel) and I like the elaborately shaped click. Quite simply, every element of the movement is distilled to the nth degree and looks fabulous.

Closing remarks

Firstly, I have to talk about the notion of using this watch for diving. I must be honest and say that in my opinion it would be sacrilege to dive in such a beautiful watch. A dive computer is cheaper and far more practical.

However, this should not be considered an impediment to acquisition. Most purchasers of a diver’s watch seldom explore the deep-sea capabilities of their timepiece. The rationale for choosing a diver’s watch is they offer a host of additional attributes, making them ideal for daily wear on terra firma.

Angelus U51 Diver Tourbillon

Typically, divers’ watches are highly legible, robust and have a useful degree of water resistance. The Angelus U51 Diver Tourbillon surpasses this inventory of user benefits with the addition of an open-worked movement, a tourbillon and a Grade 5 titanium case. Furthermore, unlike many skeleton watches, the dial is a paragon of lucidity.

From an engineering perspective, the Swiss firm has expended much energy to achieve the model’s impressive level of torsional rigidity. The twin-arm beams, the six-spoke wheels and the screws with torque optimising heads would not look out of place on a race car or jet plane.

The Angelus U51 Diver Tourbillon costs £35,000 (RRP as at 5.10.2019) and represents incredible value for money, considering its impressive specification.

Most notably, despite the myriad of qualities I have outlined herein, the primary reason why I am smitten with this watch is that it is ‘the real deal’. Unlike some convertible cars which lack rigidity and are only suitable for driving slowly and posing in front of onlookers, the Angelus U51 Diver Tourbillon can perform in the most arduous conditions and look good at the same time. Indeed, this watch is the horological equivalent of a stunning open-roofed roadster which can traverse twisty mountain roads while looking superb.

Further reading

Technical specifications

  • Model: Angelus U51 Diver Tourbillon
  • Reference: 0TDCT.E01A.K008D
  • Case: Grade 5 titanium; diameter 45mm; height 12.47mm; water resistance 30ATM (300 metres) sapphire crystals to the front and back
  • Functions: Hours; minutes; small seconds; one-minute flying tourbillon
  • Movement: Calibre A-310; hand-wound movement; frequency 28,800 VpH (4Hz); contains 23 jewels; power reserve 120 hours
  • Strap: Blue rubber strap, paired with a titanium pin buckle
  • Price: £35,000 (RRP as at 5.10.2019)

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