Review: Nomos Aqua Ahoi Datum with 200m water resistance

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Sporting 26 years of existence, Nomos is a quiet player. Not only have they managed to be present on the market all these years, they excelled at being an affordable independent brand featuring robust in-house movements. Known for their clean looking timepieces, the brand’s timepieces tended to look delicate and sensible. However, over time, the watches proved that though the look might be fragile, but they are solid. To strengthen this statement, Nomos improved further the case tightness, offering for the new Nomos Aqua Collection a 200m water resistance. Today we review the Nomos Aqua Ahoi Datum.


Nomos Glashütte i/Sa.


Even if it comes from Glashütte, Nomos does not have a common history with the rest of the well-known German brands. Our in-chief editor interviewed Nomos’ CEO Uwe Ahrendt last year. The interview contains a lot of information about the brand’s history, and we highly recommend you read it for background information.

Nomos Glashütte i/Sa. (Nomos Glashütte in Saxony) was founded by Roland Schwertner, in January 1991. The first collection featured movements from ETA Peseux but modified and decorated for Nomos. In March 2002, the heavily modified Peseux calibres were renamed Nomos 1T.



Ahoi Datum Atlantik is a casual looking piece with an easy-going colour scheme. The watch does not pretend to be a dress watch or a sporty piece but fits well an elegant outfit as well a sportier, city look.


The full recognition as a true manufacturer came in 2005. Nomos introduced the Alpha calibre used for Tangente Automatic. This movement was based on the Peseux 7001 but no major parts were shared with the ETA ebauche. Starting with 2013, Nomos watches received a finer finishing.

In 2014, the brand managed to break the dependency of the Swiss Nivarox (today’s main supplier of balance springs) by introducing their in-house escapement. The Nomos Swing System was and still is a major breakthrough. Considering the size and the sales volume of the brand, the in-house escapement is an impressive and proved to be a crowning success.

In 2016, Nomos continued to impress by releasing of an ultra-flat movement – DUW3001. The movement’s technical specifications are notable for any watch manufacturer, and a significant achievement for a small independent.


Review: Nomos Aqua


Under the name Aqua Series, Nomos presents two models (Club and Ahoi). The watches are powered by the in-house movements featuring the brands’ own Swing System escapement. Today we review the Nomos Aqua Ahoi Datum powered by the calibre DUW5101.



Nomos Ahoi Datum Signalblau is maybe the most “fun” piece of the series. The light blue dial has a young, fresh spirit.


The case, dial and hands

Nomos Aqua Ahoi Datum preserves the brand’s DNA of purity. Slowly but surely, Nomos has built, during all these years, a recognisable style. The case of the Aqua Ahoi Datum is an enjoyable wrist partner. The case is 40.3mm in diameter and a height of 10.64mm and is almost identical in construction with the Tangente’s case. The Bauhaus inspired style with a slim bezel and relatively long, slim lugs strikes us as rather elegant. The case line is “abruptly” interrupted by the crown’s protection bumps. Together with the slim crown, they create a sportier look. The two-parts construction steel case received a gentle polished finish. The back-case features, as the other Nomos models and as we expected, a see-through sapphire crystal and uses 6 screws for fixation. This component presents no other decorations, the only marks are the whale drawing (which is kind of cute) with 20atm engraving along with the watch’s name and code. To assure the water tightness, the crown is a screw-down system.



The Ahoi Datum Ref.551 has the “standard” look expected from Nomos. The neon-orange seconds’ hand cheers the seriously look of the simple dial.


The dial is similar to other models. The Nomos Aqua Ahoi Datum comes in three dial colour variants: Ahoi Datum in white, Ahoi Atlantik with a dark blue colour and Ahoi Datum Signalblau that features a Siren blue dial (light blue – azure).

The dial has a nice alternation of the hours’ indexes between Arabic numerals and baton indexes. The indexes are printed, with the minutes/seconds markers in contrasting colours to the dial. To increase the low light visibility, the hours’ markers have additional indexes with green SuperLuminova.

A nice touch is represented by the date window. This is manufactured in the same colour scheme as the rest of the dial. In this way, the dial’s face remains balanced. Nomos uses the coloured lacquered seconds’ hand from older models. The neon orange element denotes, if not sportsmanship, at least a lot of fun.



Ahoi Datum Atlantik has the darkest colours from the series. It still manage to keep a warm, pleasant look. To note the shy crown protection bumpers. They do the job without being bulky. The slim crown helps the look.


There is a slight difference between the hour and minute hands of the watches. The white-silver plated Ahoi Datum has the rhodium-plated hands with SuperLuminova inlay in light blue (green luminescence). The siren blue Ahoi Datum Signalblau has white SuperLuminova (green luminescence) while the dark blue Ahoi Datum Atlantik has the hands gold-plated and green SuperLuminova. The dial of the Atlantik is warm and soothing.

The best proof of the sporty intention of the Nomos Aqua comes from the blue-black textile strap. This sits well on the wrist and despite the material, the watch can pass easily as an authentic elegant piece. Almost like a dress watch. Almost!


The movement: DUW5101



The see-through crystal reveals the movement finished adequately, with no claims for high horology.


DUW stands for Deutsche Uhrenwerk (German Watch Movement). Manufactured and designed in-house, the DUW5101 calibre features the Nomos Swing System. This escapement is designed by Nomos and comprises of the balance, balance spring, escape wheel and pallet. The self-winding movement has a decent 42 hours of power reserve. The decorations are adequate and well done for a machined finished movement. A nice view is the blue tempered balance spring, accompanied by blue screws. In opposition, the Glashütte three-quarter plate is rhodium plated and the surfaces are adorned with Glashütte ribbing (Côtes de Genève) and NOMOS perlage.

The DUW5101 is a pleasant view, worthy to spend some time for a closer study.



DUW5101 is nicely decorated. A close look reveals the machine finishing. An easily visible detail is the finish of the bevelled edges. Taking into consideration the lower price, the level of the decoration is acceptable.


Competitive landscape


The Nomos Aqua Ahoi Datum is politely priced at €3,500 for the Ahoi Datum white silver dial and €3,620 for the Ahoi Datum Atlantik and Signalblau. Why “politely”? The brand uses an in-house calibre, totally independent. Having their own escapement, the brand is situated high, between great players. On the other hand, the finishes are machine made. Also, the brand doesn’t have the particular glamour of some of the competition. These borderline particularities make it hard to find a one to one competitor. The reason: full independent brands (including the ones with “a la Maison” balance springs) have much higher prices, the similar micro brands with ebauche movements are lower priced.

The first “equivalent” timepiece is the Seiko Presage Cocktail Time from the Prestige line. An elegant case with 40.5mm diameter and dual-curved sapphire crystal with an impressive look. The 10bar water resistance makes of this beauty a small beast. The exquisite enamel dial with roman numerals and blue hands deserves a lot of attention. The watch is much more classic in comparison with our piece. The Seiko Presage SPB047J1 is powered by an in-house movement, the Seiko calibre 6R15: 50 hours of power reserve for a slow for this days, 3Hz balance wheel. This movement misses the beautiful decoration of the haute horlogerie counterparts. The only decorations are decently machined finishes. With a price tag of €1,100, this watch is a winning card in its price category.

Another proposal comes from Germany: Sinn 1736 Klassik. Its case is much smaller, only 36mm diameter. This watch goes powerfully in the dress watch direction. It still bids 10bar water resistance, features a white enamel dial with roman numerals, as the Japanese rival but comes with an ETA2892-A2 movement. The Swiss calibre features a 28,800vph (the modern 4Hz) balance wheel and offers 42 hours of power reserve. The movement features the standard perlage and Côtes de Genève with Sinn personalisation for the rotor. The watch is available on the brand’s website for a price of €1,590.

Concluding thoughts

Nomos Aqua Ahoi Datum is a beautiful watch. It manages to be the hard working but funny guy that all love. The wrist presence is enjoyable due to its calm and versatile design. The calibre is a powerful achievement, especially considering their own balance spring and escapement.

Now, the debate about in-house versus well-known ebauche makes no sense. The exclusivity of the maison movement at such a low price is almost overwhelming. The ETA calibre has the advantage of easy repair in case of need. But how many times have we heard of a watch to need extensive repairs in normal usage?

If you are not a hand-finishes freak and you desire a full in-house timepiece, we might add: with robustness proved in the last 20 years, the Ahoi Datum is a good choice.

Nomos Aqua Ahoi Datum Specification and Price

Recommended Retail Prices: Ahoi Datum Ref.551 €3,500 (VAT incl.), Ahoi Datum Atlantik Ref.553 and Ahoi Datum Signalblau Ref.554 €3,620 (VAT incl.). The timepieces are available for order direct on Nomos Website.



Calibre: DUW5101

Type: mechanical self-winding movement

Dimensions: diameter 31 mm, thickness 4.3mm

Jewels: 26

Power reserve: 42 hours

Frequency: 4 Hz / 28’800

Functions: Hours, minutes, small seconds, date



Material: stainless steel

Dimensions of the case

Diameter: Ø 40.3 mm; height 10.64 mm

Crystal: curved sapphire crystal glass

Crown: stainless steel, screw-in

Caseback: see-through sapphire case back

Water resistance: 20atm / 200m



Material: textile strap blue-black

Buckle: winged steel clasp


1 Comment

  1. If they just managed to put a well integrated thin rotating bezel on this one it would be a must have watch and a very unique diver and instant best seller for Nomos.