Caring for a Fifty Fathoms Strap After Salt Water
The Scuba Fifty Fathoms is one of the few watches at its price that genuinely belongs in the sea. Rated to 9.1 bar, the case takes salt water without complaint. The strap is where the damage quietly accumulates, and almost all of it happens in the hours after the swim rather than during it. Whichever band you wear from our range of straps for the Fifty Fathoms, the routine below takes about a minute and is the single biggest factor in whether it still looks right in three years.
Salt is the problem, not water
What salt actually does to a strap
Sea water carries roughly thirty-five grams of dissolved salt per litre, and when it evaporates the salt stays behind as fine, hard crystals. On a strap they settle exactly where you cannot see them: inside rubber perforations, between the fibres of a nylon weave, in the gap where a leather lining meets its stitching, between the links of a bracelet. Every time the strap flexes, those crystals grind at the material from the inside.
That abrasion is behind most of what owners describe as a strap simply wearing out. Rubber develops a dull, chalky surface and cracks at the lug ends. Nylon frays at the keepers. Leather stiffens into a shape it will not come out of. Salt is also hygroscopic: it pulls moisture out of the air and holds it against the material long after the strap feels dry, which is why a band that was never rinsed smells sour weeks later.
Why rinsing beats every product you can buy
There is a small industry selling sprays and wipes for this, and none of them do anything fresh water does not do better. Salt is highly soluble: thirty seconds under a cold tap carries away almost all of it, while a wipe mostly redistributes it. Chlorine is the same story, and in some ways more urgent.
The sixty-second routine
Rinse with the buckle open
Take the watch off, open the buckle fully and run the strap under a cold tap. Cold, not warm: heat opens up rubber and drives salt further in rather than flushing it out. Work the water through with your fingers — along both edges, through the perforations, into the buckle holes and around the tang. On a beach with no tap, a bottle of drinking water does the job. What does not work is waiting until you get home, because once the salt has dried in, a rinse removes far less of it.
Dry flat, shaded and completely
Lay the strap flat on a towel, out of direct sun and away from any radiator, car dashboard or hot windowsill. Much above 40°C softens rubber and can deform it permanently at the lug ends, and the same heat shrinks textile and cracks leather. Rubber dries in under an hour, nylon in one to two, canvas and leather in four to six — and they want the full time, because refitting a damp strap traps moisture against the case back and around the bar holes.
Material by material
Rubber: the easy case, with one caveat
Rubber absorbs no water, so salt sits on the surface and rinses straight off. The caveat is the perforations: each hole is a small reservoir where salt concentrates, so squeeze along the strap under the tap rather than holding it in the stream. Sun cream matters here too — most formulations contain oils that soften cheap rubber, so after a day of both, use a drop of mild soap rather than water alone.
Nylon and canvas: rinse, then be patient
Textile punishes neglect most visibly. Nylon holds salt deep in the weave and dries in about an hour; woven canvas holds more and takes several. Both need the water worked right through with your fingers, and both should be dried flat rather than hung, because hanging a wet textile strap pulls the weave out of shape at the keeper. The compensation is that textile takes repeated washing better than anything else — a good canvas strap for the Fifty Fathoms survives dozens of cycles, provided the edges are heat-sealed or stitched rather than raw cut.
Leather: keep it out of the sea entirely
Salt water and leather are a short relationship. The water swells the fibres, the salt stays in them, and the drying that follows pulls the strap into a stiff, wavy shape that no amount of balm reverses. If a leather band gets splashed, wipe it with a barely damp cloth, dry it with a second cloth and let it rest overnight away from heat. If it gets properly soaked, accept that it will never be quite the same. The sensible approach is not to wear leather on a day that involves the sea, which is the whole argument for owning a second strap.
Steel: rinse the clasp, not just the links
Good 316L stainless steel resists corrosion well, which makes owners complacent. The vulnerable part is not the outside of the links but the inside of the clasp, where salt water collects in the folding mechanism and stays. Rinse with the clasp open, flush it deliberately, then dry inside it — a corner of kitchen roll works. Plated base metal is another matter: sea water starts pitting it within a single summer, which is why a steel bracelet for the Fifty Fathoms is worth buying on specification rather than on photographs.
The hardware nobody thinks to rinse
Straps rarely fail in the middle. They fail at the buckle, where the tang works the holes oval, and at the keepers — which is also where salt concentrates most, since both hold water by capillary action long after the rest of the strap has dried. Thirty seconds with the buckle open and a deliberate flush around the tang pin is worth more than anything you do to the body of the strap.
One detail specific to this watch: the Fifty Fathoms uses screw bars, and the caps sit in threaded holes that happily hold salt water. If the watch swims regularly, check them with a 0.9mm hex driver every couple of months — a cap seized by corrosion is far more trouble than one simply loose.
The weekly wash
Rinsing handles salt. Skin oil, sweat and sun cream need soap, and once a week is enough for a watch in regular use. Lukewarm water, one drop of mild washing-up liquid, a soft toothbrush along both edges and around the buckle holes, then a thorough rinse — leftover soap is what makes a clean strap feel tacky. Take the strap off the watch for this: the case is rated to 9.1 bar, but there is no reason to push detergent into the lug area.
Keep alcohol gel, antibacterial wipes, acetone and bleach away from every material: they strip the plasticisers out of rubber, fade dyed textile and ruin leather outright. A pale band that has picked up denim dye responds well to a thin paste of bicarbonate of soda, applied with a toothbrush and rinsed after two minutes.
Mistakes that age a strap fastest
Leaving the rinse until tomorrow, which lets the salt dry fully into the material. Drying on a radiator, in a car or in direct sun. Refitting a damp strap and putting the watch away. Wearing one band continuously through a beach holiday instead of alternating two. And washing a strap in the machine, where heat and agitation finish off in forty minutes what the sea would need two seasons to achieve.
Frequently asked questions
Do I really need to rinse after every sea swim?
Yes, and the sooner the better. Thirty seconds of cold fresh water removes almost all the salt; waiting until it has dried in removes far less.
Is chlorine worse than sea water?
In some respects. It attacks rubber and textile dyes chemically rather than abrasively, so rinse after a pool exactly as you would after the sea.
Can I leave the strap on the watch while rinsing?
For a quick rinse, yes. For the weekly soap wash, take it off.
My strap still smells after rinsing. What now?
Wash it with mild soap, rinse twice and dry it fully flat. A smell that survives that means the material has absorbed too much and the band is near its end.
How long should a strap last with sea use?
A well-made FKM rubber or sealed-edge nylon band takes two to three years of regular swimming if it is rinsed. The same strap unrinsed often cracks inside a year.
A minute now, or a new strap later
The Fifty Fathoms is a diver that owners actually swim with, which is rather the point of it, and the case will outlast several straps regardless of what you do. Whether each of those straps lasts three years or nine months comes down to one habit: cold fresh water with the buckle open, straight after the swim, then dried flat and shaded until genuinely dry. Alternating two bands across a holiday makes it easier still. Nothing here is difficult, and no product you can buy improves on it.
Also read our previous article: The Five Most Common Mistakes When Changing a MoonSwatch Strap