Diving with a Scuba Fifty Fathoms: What the Strap Must Handle
The Scuba Fifty Fathoms is the one Swatch collaboration built around water from the outset, and the strap is the part of it that takes the punishment. Ninety-one metres of water resistance looks after the movement; nothing looks after the band except the material it is made from and what you do with it afterwards. Everything in our Fifty Fathoms straps range is cut to 22mm for this case, but width is the easy part. What follows is what a strap actually has to survive once the watch goes in the sea, and how to pick one that will still look right in two years.
What ninety-one metres actually covers
Ninety-one metres is fifty fathoms, which is where the name comes from. It is a static pressure rating, established in a laboratory on a watch that is not moving — real water is more demanding, since a hand entering the sea at speed or a wave against the wrist loads the case far beyond the depth on the dial. In practice the rating comfortably covers swimming, snorkelling and everything at the surface, and it is sensible to treat this as a water-capable watch rather than a piece of dive equipment. The case is sealed; the strap is not, and it lives in the same conditions with no protection at all — salt water, direct sun, sand at the beach, chlorine at the pool, and the same two flex points every time you fasten the buckle. That combination, not depth, is what actually ends the life of a band on this watch.
Salt water is the real test
Sea water leaves salt crystals behind as it dries, and those crystals are abrasive. On rubber they collect in the perforations and along the folded edges, working like a fine grit every time the strap bends. On textile they settle into the weave, which is why a NATO dried untreated after a swim feels stiff the next morning. On leather the effect is worse: salt draws moisture out of the fibres, and a leather band soaked and dried a few times becomes brittle at the fold. Hardware suffers too — salt sitting in a buckle pin hole is enough to start surface pitting on lower-grade steel within a single holiday. Thirty seconds under a cold tap, immediately, does more than any product you can buy: unfasten the buckle so fresh water reaches the underside, run water through the perforations, then pat dry and leave flat somewhere shaded. Sand deserves the same treatment, since grains trapped between band and lug will mark bioceramic given a few days of wear.
Materials, judged by the water
FKM is the material this watch was made for: chemically stable, it does not absorb water, salt sits on the surface rather than soaking in, and it shrugs off UV and chlorine in a way silicone does not. It also holds its shape, which matters on a case this size — a band that has softened and stretched will let a heavy watch rotate on the wrist. Our Fifty Fathoms rubber straps are cut for the 22mm fitting and screw bar hardware this case uses. Silicone is cheaper and softer, but attracts dust, marks more easily and gives up sooner under sun and salt.
A NATO threads underneath the case rather than sitting between the lugs, so the watch stays attached even if one bar fails, and nylon dries quickly and washes easily — but it lifts the watch a millimetre or two off the wrist, noticeable on a case already 14.4mm thick, and wet nylon holds water against the skin longer than rubber does. Canvas is handsome and comfortable but slower to dry, so it belongs to warm days rather than swimming. Leather has no place in salt water: it will survive a splash and a prompt wipe, but repeated soaking and drying destroys it from the inside. Steel is immune to salt if you rinse it, and suits the proportions of this watch, at the cost of extra weight and a clasp that needs drying properly rather than shaking off.
Fit in the water is not fit on land
Cold water contracts the wrist, sometimes enough to move you a full hole on the strap; heat and exercise do the opposite. A band adjusted perfectly on a warm terrace will be loose in the sea, and a 42.3mm watch that rotates underwater feels considerably heavier than it is. Buy a strap with holes close enough together to give a genuine choice, and check the fit once you are actually in the water. A flapping tail is an annoyance on land and a liability in water, where it catches on wetsuit cuffs — two keepers are better than one, and a slack keeper should be replaced rather than tolerated. If you dive with a wetsuit, remember the strap has to clear the neoprene cuff, which usually means a longer strap or extension rather than a tighter buckle.
Screw bars, sand and the hardware you cannot see
The Scuba uses screw bars rather than spring bars, which is good news for water use — no spring to weaken and no compressed pin to work loose. It does mean the threads want checking: salt and fine sand find their way into the lug holes, and a cap left slightly loose will back out over weeks of wear. Check both caps with two 0.9mm hex drivers every couple of months if the watch swims regularly, and tighten firmly without forcing — bioceramic threads do not forgive over-tightening. This five-minute check is the single most useful piece of maintenance on this watch, and almost nobody does it.
Colour and the ocean editions
Water strips colour with depth, red first, then orange and yellow, which is why high-visibility dive straps tend to be white, yellow or orange rather than red. There is a practical side too: a pale strap shows sand and sun cream immediately, a useful prompt to rinse it. Since the case and fitting are identical across the range you can borrow freely between editions — our straps by Fifty Fathoms edition are grouped that way for exactly this reason.
Five minutes after the swim
Rinse the strap and case under fresh cold water with the buckle open, working water through the perforations or weave with your fingers. Pat dry with a cloth, then leave the watch flat and shaded for an hour before putting it away — a strap stored damp against a caseback is how corrosion and odour both start. Once a month, take the strap off entirely and wash it properly in lukewarm soapy water. If the strap is textile, that monthly wash is not optional: nylon holds salt long after it feels dry.
Frequently asked questions
Can I actually swim in the Scuba Fifty Fathoms?
Yes. Ninety-one metres covers swimming and snorkelling comfortably — treat it as water-capable rather than professional dive equipment.
Which strap material is best for the sea?
FKM rubber. It does not absorb water, resists salt, chlorine and UV, and keeps its shape on a heavy case.
Do I need to rinse after every swim?
After salt water and chlorinated pools, always. Thirty seconds under a cold tap prevents most of the damage that ends a strap's life.
Will the screw bars corrode?
Not readily, but salt and sand collect in the lug holes — check the caps are tight every couple of months if the watch swims often.
Buy for the water, not for the photograph
A strap that works in the sea is not the same as a strap that photographs well on a desk. The one that lasts is stable in salt, quick to dry, adjustable enough to cope with a wrist that changes size in cold water, and fitted with hardware that gets checked occasionally rather than trusted indefinitely. Get that right and the Scuba Fifty Fathoms does what it was designed to do, year after year, without the band becoming the weak point.
Ready to gear up? Browse our full collection of straps for the Blancpain x Swatch Fifty Fathoms.
Also read our previous article: FKM vs Silicone: Which Rubber Strap Suits Your MoonSwatch?