The Sinns of the Fatherland

When the maritime wing of the German border protection group needed a near-indestructible watch, it turned to Sinn

THE GSG9 –the 9–isthe German Federal Police’s border protection group. Although it sounds a little like the UK’s Border Force, they are as far removed from the nice people who welcome you back to Dover after a drive back from Le Mans as could be. Founded after the Black September attack on the 1972 Munich Olympics, they are, in effect, a highly specialised paramilitary section of the German Police. Rather than issuing parking tickets, GSG9 does the hardcore, serious stuff such as anti-terrorist arrests or hostage rescues.

As well as rappelling from helicopters and freeing people from hijacked aircraft, they also operate a maritime unit. These are the chaps you’ ll be delighted to see if pirates have boarded your oil tanker, or when uninvited blokes with Kalashnikovs shin up your gas platform.

When GSG9 wanted a watch specially made for its officers, it approached watchmaker Sinn. Based in Frankfurt am Main since 1961, the firm had been founded by former WW2 pilot Helmut Sinn. Since then, it has put watches in space, under water, in racing cars and subjected them to distinctly unfriendly treatment, so it was high on GSG9’s list of potential suppliers.

In the mid-1990s, GSG9’s maritime specialists asked Sinn to make a watch that would stand up to daft levels of abuse and also be much more legible under water, wouldn’t fog no matter what, and would survive to any practical depth. That would have been an interesting meeting to sit in on.

Sinn describes the process of developing an ultra-robust, practically depth-proof, non-fog watch as ‘the most cost-intensive and challenging research we have ever done’. Given that its D-2 chronograph went up with the space shuttle and flew 6.7 million kilometres, orbiting the earth 160 times, that’s quite a claim.

The conventional approach would be to make the case, seals and crystal thicker, heavier and more robust, but that falls down because the air in the watchcase would still allow the crystal to fog. Also, because air has a different refractive index from water, it’s easy to accidentally angle a standard diving watch under water so the crystal appears like a mirror – you can’t see the dial or hands.

However, Sinn’s owner and general manager, Lothar Schmidt, realised there was a neat way simultaneously to make the GSG9 watches waterproof, stop the fogging and prevent the mirror effect. Where most watch cases are made to keep things like water and dust out, Sinn’s would be designed to keep something in: low-viscosity oil. The liquid inside the watchcase would be practically incompressible, making the watch near-as-dammit depthproof, but the oil would also stop any fogging and, crucially, fix the refraction problem.

The challenge then emerged of what movement to put inside the new case, by then christened the HYDRO. Mechanical was a non-starter because, although the case-filling fluid was low-viscosity, it was still thick enough to smother even a powerful mechanical engine’s balance wheel. The HYDRO watches had to be quartz, which will run happily immersed in an inert oil. Even so, you still need a movement with serious torque to move the hands, so Sinn opted for ETA 955.652 – a thermocompensated quartz that’s accurate to ±10sec a year. It’s understandably cagey when asked about modifications: ‘The HYDRO department has to adapt some parts of the movement, but we’re not talking about that in detail.’

It’s not as simple as just pumping in a bit of oil, screwing the back on and nipping off for

Instead, the cases (they’re cut from the same steel as Germany ’s submarine fleet) have a membrane engineered into the caseback that allows the oil in the watch to adjust constantly to the pressure around it.

Sinn has tested HYDRO watches to 500bar, or just over 5000m. That’s the point at which the tiny capsule holding the quartz crystal buckles. The case itself is happy down to 12,000m and –20 to +60°C, which is more than could be said of any GSG9 officer who’d be wearing it. It’s probably fair to describe Sinn’s HYDRO watches as ‘over-engineered’.

Although a rusty bucket with a hole by comparison with Sinn’s achievements, the

team has put together its own ultradepth watch by filling a Casio F-91 digital with the sort of oil you use to keep treadmills running smoothly. Now we’re looking for a reader with serious underwater exploration facilities willing to test it for us to a daft depth and report back.

Emails to the usual address, please.

‘THE CASE IS HAPPY DOWN TO 12,000M, AND FROM -20 TO +60°C… MORE THAN COULD BE SAID OF ANY GSG9 OFFICER WEARING ONE’