Few watches in the history of horology have left as wide and lasting an impression as the Patek Philippe Nautilus has, except perhaps its spiritual brother, the Audemars Piguet Royal Oak. Unsurprisingly, these two have become the grail watch for many enthusiasts today.

The Nautilus did not debut with a bang, however. There was not a lot of hype and anticipation for it when it was released in 1976. Sales were slow in its first few years until a ladies’ version was made 4 years later, and a smaller-sized version another year after that. 


We're guessing the advertising strategy paid off. Source: The Watch Lounge


It’s a sports watch made of steel, and yet it was priced much higher than 18k gold Patek Philippe watches that preceded it. In fact, it was the most expensive sports watch of its era, costing as much as a third of the median annual salary in the US. Even their advertising slogan banked on the ridiculous idea of a steel watch with a high price tag: “One of the world’s costliest watches is made of steel.”

Today, the Nautilus is the brand’s ambassador with insatiable demand from its fans.


From Humble Beginnings

The Nautilus was not a watch that took many years of conceptualization and design. The famous story is that this era-defining watch took 5 minutes from idea to sketch before being pitched to the executives at Patek Philippe. It may sound like an unbelievably short time, but it was enough for the legendary Gerald Genta to create.


The resemblance is clear. Source: Monochrome Watches


In a 2009 Interview with horology writer Constantin Stikas, Gerald briefly explained how the Nautilus was conceived. At a 1972 Basel Trade Fair, he was having a solo dinner at a hotel restaurant when people from Patek sat at a corner opposite him. He had asked a waiter for something to sketch on, and on the spot came up with the iconic ship porthole-looking watch.

The Nautilus Look

In their primary sketches, the Patek Philippe Nautilus looked quite similar to the Audemars Piguet Royal Oak, but there was enough distinction between the two to separate the Patek piece from its predecessor.

The shape of the face is inspired by a ship’s porthole; the octagonal shape of the bezel has rounded corners that are secured by lateral screws. There are also the notable “ears” on the sides. These ears are the case’s crown guard on its usual spot, and a hinge on the left side of the case. 


Rumor has it that Patek Phillipe is not entirely thrilled that the Nautilus is the best performing watch in all their lineup. Source: Money Inc


Why a hinge? This is because the watch only opens from the front. It does not have a removable caseback like other watches of the time, and instead features a monobloc body. This was done to achieve the 120m water resistance rating that was considered a feat for the sports watch. If you need to service the movement for any reason, you’ll have to bring it out the front.

The construction material is not just ordinary steel, but an alloy of nickel, chrome and molybdenum. This is the same material used for WWII tanks, lending great durability to the watch and the perfect choice for a sports-oriented timepiece. It can withstand high temperatures and pressure and is also lighter than other steel materials. No doubt, the target market for the watch, which were dynamic businessmen, appreciated the Nautilus’s features.


A Forgotten Seiko Cousin

Gerald Genta was an incredibly prolific designer of watches, with hundreds of thousands of designs created over decades, for a countless number of watch brands and individual commissioners. It is unsurprising that some of these pieces will be forgotten from the limelight, and one of these models was made in 1979 for then Seiko president Reijiro Hattori, dubbed the Seiko Credor Locomotive.


Reijiro Hattori was a big Gerald Genta fan. Source: Watchuseek


It’s an instantly recognizable design language, with its octagonal bezel and exposed screws.

It has a very clear resemblance to the Royal Oak and Nautilus, but while the previous two were respectively inspired by a diver’s helmet and a ship’s porthole, the inspiration for the Seiko Credor Locomotive is right there in the name. This Gerald Genta-designed watch looked at trains for its elements. 

Sadly, only 5000 pieces was ever produced which was reserved to the most avid fans of the late watch designer, or Seiko.


The Seikonaut

Aside from the Seiko Credor Locomotive, Seiko actually released a watch lineup that looks quite close to the Nautilus, earning it the “Seikonaut” nickname. This is the SNKK4X series.

Undoubtedly, the porthole-shaped case drew the comparison to the Nautilus, and you can say it’s just one octagonal bezel away from being a copy. It still has that Seiko 5 charm, and the very affordable price made the Seikonaut an instant hit with Seiko fans. Demand for the watch never ceased despite the series being discontinued


It's got the looks, and comes with a friendly price tag back when it was still being produced. Source: Watch Charts


The SNKK4X series is part of the Seiko 5 Sports line, characterized by its small size and a relatively thin body. It uses the ever popular 7S26 movement inside and is also fitted with Seiko’s Diashock system. It’s a beater watch that you can wear everyday for many years before needing a service, and is a great value under $200 if you can find it on the secondary market.

Modding your Seikonaut

Amid the bustling week before Black Friday, namokiMODS has stealthily released 4 versions of an SKX007 Nautilus case so you can mod your own Seikonaut at home. This case is inspired by the actual Patek Philippe Nautilus, so aside from the porthole shape, it also features the iconic octagonal bezel already integrated into the case. The flat crystal and chapter ring is already installed for your convenience.



If you want to capture the feel of the original Nautilus, you would want to go for the polished finish version. It may not be the same alloy used in tanks anymore, but you’ll find that the look and finish is spot on. Just pick your preferred crown, dial, hands and caseback and you have your very own Seikonaut mod.

And if you want something fancier looking, you can take inspiration from the SNKK52 and choose the gold finish version for your mod. Be sure to match it with a sapphire display caseback to get the full effect.



Don’t forget to check out the PVD black finish for stealth mod fans, or the rose gold finish for your dressy Seikonaut.

Seiko Modding with Namoki

namokiMODS is one of the well-known and trusted Seiko mod parts suppliers in the space, and we offer a wide variety of parts and designs with premium quality.

We have parts not only for the modding favorite SKX007, but also for the SKX013, SRP Turtle, and recently, the SRPE 5 Sports series. We are adding support for more and more watches so be sure to check back from time to time for our latest releases!

We have also recently released NATO and rubber straps on the store, as well as Titanium SKX007 and MM300 cases. Check out all of our latest releases here.

Happy modding!

December 03, 2021 — Jeremiah A


Enoch said:

Will the Nautilus fit a standard 28mm Seiko dial??

Peter said:

Good question, searching the same, rather by here than on ebay etc, you can try the explorer bracelet, but the Patek Phillipe bracelet is not in the store it seems, hope they will sell these in the upcoming future!

Nut said:

I have Seiko samurai automatic 200 m
You can make case ?

Cheung Gar Tin said:


Nicolas said:

First of all, nice article and case!
But what bracelet is compatible with this type of case?

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