Blancpain’s sporty new Fifty Fathoms Tech BOC IV supports a good cause in style
Jamie WeissOver the years, Blancpain has taken the Fifty Fathoms in wildly different directions – the Bathyscaphe Complete Calendar Moonphase in ceramic, which manages to be both utilitarian and maximalist all at once, or the monstrous X Fathoms, which features a 55.6mm case and a mechanical depth gauge. Another distinctive Fifty Fathoms incarnation was the Tech Gombessa, released as the second act in a trio of watches celebrating the Fifty Fathoms’ 70th anniversary in 2023. The Fifty Fathoms 70th Anniversary Act 2: Tech Gombessa was notable for having an interesting almost lugless design as well as a special hand that completes one full turn every three hours to time longer dives, with a corresponding 3-hour timing bezel to boot.
It was a cool watch, but one with a rather specialised complication – and measuring 47mm in diameter, it’s not a watch that just anyone can pull off. However, the new Fifty Fathoms Tech BOC IV takes the Tech Gombessa’s appealing case design and shrinks it down to more daily-wear proportions, while also returning to a more conventional dive watch format and supporting a worthy charitable endeavour.
The case
The Blancpain Fifty Fathoms Tech BOC IV features a 45mm wide (i.e. 2mm smaller than the Tech Gombessa), 14.1mm thick case made from grade 23 titanium. Due to its lower oxygen content, grade 23 titanium enjoys better biocompatibility – which is why it’s favoured in surgery – compared to grade 5 titanium. These aren’t petite dimensions by any means, but the Tech BOC IV actually wears smaller than that 45mm number suggests. Because its case is almost pebble-like, utilising central lugs and an integrated strap, it looks like a smaller watch than it is on the wrist, especially top-down. That said, because of that central lug design, the first half a centimetre or so of strap doesn’t fully articulate… However, it hugs the wrist, so again, it’s more wearable than you might think. Because it’s titanium, it’s pleasantly light, too.
Unlike the Tech Gombessa, it features a standard (i.e. 60-minute-marked) unidirectional diving bezel with a subtly domed ceramic insert, which nicely frames the similarly subtly domed crystal. Also, its bezel is one of the best I’ve ever used. It’s quite loud and clicky, but in a very satisfying way. It retains a 300 metre water-resistance rating, which is standard across the entire Fifty Fathoms range, yet features a helium escape valve at 10 o’clock, which is atypical for a Fifty Fathoms. You’ll also find the Blancpain logomark engraved across the left-hand side of the case, shifted downwards somewhat to accommodate the helium escape valve.
The dial
Rather than go for a flashy orange or shimmery sunburst, the Blancpain Fifty Fathoms Tech BOC IV’s dial is the same glossy “Absolute Black” as the Tech Gombessa. Blancpain explains that Absolute Black absorbs up to 97% of light, which helps the dial indications stand out in deeper waters. It’s quite something to observe in real life: it’s not quite as black hole-like as Vantablack, for example, but it’s still utterly eye-catching. At some angles, the dial almost appears to be filled with oil, like the Sinn HYDRO range of divers – but those are quartz, and you’ve still got a smoothly sweeping seconds hand here! Speaking of that hand, it’s coloured blue, as is the ‘Tech’ text on the dial, distinguishing this Fifty Fathoms from all others even at a distance.
Another point of difference between the Tech Gombessa and Tech BOC IV is that the latter now features a date window at 4:30, like standard Fifty Fathoms Automatique models. 4:30 dates are always a bit contentious, but I think it provides a visual counterbalance to the helium escape valve opposite. The numerals on the date window use the same curvaceous, futuristic font as the cardinal numerals and ‘Tech’ text on the dial, which is a nice touch.
The strap
As alluded to earlier in this review, the Blancpain Fifty Fathoms Tech BOC IV has an integrated rubber strap, sporting a chunky grade 23 titanium pin buckle. Call me a dork, but I love that the ‘Tech’ logo is engraved into the head of the pin, matching the cursive ‘Fifty Fathoms’ across the tang. The strap is quite comfortable, appropriately sporty and I imagine would feel even better underwater. Two hex-head bolts affix the strap to the Tech BOC IV’s case – I’m not sure if a quick-release system would add anything here, as there’s no other straps for this watch (a titanium bracelet would be cool, though…)
The movement
Powering the Blancpain Fifty Fathoms Tech BOC IV is the in-house calibre 1315A – a common movement across the Fifty Fathoms range – which has a 5-day power reserve thanks to three series-coupled barrels plus an anti-magnetic silicon hairspring. A minimalist 18 ct gold rotor with the Blancpain Ocean Commitment logo (more on that in a second) swings above, exposing much of the movement underneath – which is a good thing, as it’s pleasingly finished, with subtle waves, beveling and interior angles.
The charity
You might be asking what the BOC IV part of this watch’s name means. It stands for the Blancpain Ocean Commitment, and denotes that it’s the fourth special edition watch produced in support of this program. For the last 20 years, Blancpain has been funding and supporting ocean conservation efforts around the world through their Ocean Commitment: the BOC IV specifically supports the Sulubaaï Marine Research Center in the Philippines, which Blancpain funded the construction of. This centre facilitates the study, restoration and protection of Shark Fin Bay, one of the most biodiverse marine areas in the world that’s been damaged by unsustainable fishing. €1,000 from the proceeds of each Fifty Fathoms Tech BOC Four will be donated to the Sulubaaï Marine Research Center.
The verdict
Simply put, the Blancpain Fifty Fathoms Tech BOC IV is one of the most distinctive modern Fifty Fathoms watches, and in my opinion, one of the most compelling. Mechanical dive watches are something of an anachronism – we all know this – but the Tech BOC IV offers a more modern take on the formula, with its lugless grade 23 titanium case and lume block indices standing out as particularly contemporary. If the standard Fifty Fathoms Automatique is a classic 911, the Tech BOC IV is a modern 911 Turbo: underpinned by heritage design cues but sportier; more extraordinary.
The Fifty Fathoms 70th Anniversary Act 2: Tech Gombessa – which I’ve mentioned multiple times in this article, because the Tech BOC IV is ultimately derivative of it – is arguably an even more contemporary watch. But it’s also a more niche offering (if you’re not a saturation diver, that is). Making the Tech Gombessa’s appealing case design more approachable is a masterstroke… That the Tech BOC IV also supports a good cause is just icing on the cake.
Blancpain Fifty Fathoms Tech BOC IV pricing and availability
The Blancpain Fifty Fathoms Tech BOC IV is a limited edition of 100 numbered pieces and is available now. Each of the 100 timepieces comes with a Pelican case-style waterproof box, a donation certificate, and a special edition photograph in a series of 100 prints, numbered to match the watch’s serial number, and signed by the photographer, marine biologist and filmmaker Laurent Ballesta. Part of his award-winning series from the 2023 Wildlife Photographer of the Year grand prize, it depicts a horseshoe crab in its natural habitat around Pangatalan Island in Shark Fin Bay – a great reminder of the wildlife this watch is helping protect. Price: US$21,300, A$33,900
| Brand | Blancpain |
| Model | Fifty Fathoms Fifty Fathoms Tech BOC IV |
| Reference Number | 5029A-12B30-64A |
| Case Dimensions | 45mm (D) x 14.1mm (T) |
| Case Material | Grade 23 titanium, ceramic bezel insert |
| Water Resistance | 300 metres, screw-down crown |
| Crystal(s) | Sapphire front and back |
| Dial | Absolute Black |
| Lug Width | Integrated |
| Strap | Integrated rubber strap, grade 23 titanium pin buckle |
| Movement | Calibre 1315A, in-house, automatic |
| Power Reserve | 120 hours (5 days) |
| Functions | Hours, minutes, seconds, date, unidirectional diving bezel, helium escape valve |
| Availability | Limited edition of 100 numbered pieces |
| Price | US$21,300 A$33,900 |