Who’s right about water resistance?

[jimmy156]

So I had always assumed that the water resistance stated on a watch by the manufacturer was accurate. As such, with my seiko 5 being water resistant to 3bar (30 meters) I have undertaken various activities that don’t exceed submerging it below 30 meters. So it has stayed on for car washing, bathing my son, swimming in pools, swimming in the ocean, paddle boarding, kayaking etc. its 9 years old and works fine.

If pretty much every internet site / forum is to be believed. 3 bar water resistance is only good for leaving your watch on while you wash your hands, and you should try not to get it too wet!

So who is right? The internet / watch forums, or the manufacturer, and why the discrepancy?

[r159]

Personally anything with 50m I would have no problems getting properly wet (as long as I know it’s history)

Brands such as Seiko, Citizen & Casio have a solid reputation the splash proof thing seems to be arse covering nowadays.

In the 70s 80s and 90s a watch stated it’s depth such as 30m rather just the 30m/splash proof.

Personally I think there a right load of old bks talked about this kind of thing, whereby unless it’s screw down this and that it will somehow end up doing an impression of Wicked Witch of the West near water. Don’t get me started on those idiots who start going on about waving you arm about underwater…

Having said all that, the only way to be 100% sure is to have a Diver’s watch which means that individual watch you have bought has been tested (to 125% of its rating).

[bigandclever]

Isn’t this going to come down to what the ISO standard is? Like, your 3 bar, or whatever, watch may well actually be great for swimming in, but if the standard is ‘ok for splashing but no more’ then that’s what the manufacturer will go with.

[gregs656]

jimmy156 said:

So I had always assumed that the water resistance stated on a watch by the manufacturer was accurate. As such, with my seiko 5 being water resistant to 3bar (30 meters) I have undertaken various activities that don’t exceed submerging it below 30 meters. So it has stayed on for car washing, bathing my son, swimming in pools, swimming in the ocean, paddle boarding, kayaking etc. its 9 years old and works fine.

If pretty much every internet site / forum is to be believed. 3 bar water resistance is only good for leaving your watch on while you wash your hands, and you should try not to get it too wet!

So who is right? The internet / watch forums, or the manufacturer, and why the discrepancy?

The manufacturer.

There is a ton of received wisdom on water resistance, I think a lot of it comes from marketing in the 70s and prior to that when reliable water resistance hadn’t been entirely figured out.

It won’t be long until someone brings up ‘dynamic’ and ‘static’ pressure, more received wisdom and confirmation bias; gaskets do compress, rubber hardens and so on, but people know about ‘dynamic pressure’ so that’s what gets blamed and the story continues.

Even something with no stated water resistance like an f91 could comfortably handle the depth most people go diving to.

[Kuroblack350]

Manufacturer in the main, some more believeable than others

(Shameless pic of the UX)

[jimmy156]

bigandclever said:

Isn’t this going to come down to what the ISO standard is? Like, your 3 bar, or whatever, watch may well actually be great for swimming in, but if the standard is ‘ok for splashing but no more’ then that’s what the manufacturer will go with.

Quite, this is my point really. If the manufacturer claims “water resistant to 30m” surely it has to be just that. Not splash proof.

This chart is typical of what you get if you google it. I.e in order to swim in your watch, where it will be less then 1m under the surface, you need a watch that is water resistant to 100m depth.

[bigandclever]

jimmy156 said:

Quite, this is my point really. If the manufacturer claims “water resistant to 30m” surely it has to be just that. Not splash proof.

Weasel words, innit. Water resistant isn’t waterproof.

[gregs656]

jimmy156 said:

Quite, this is my point really. If the manufacturer claims “water resistant to 30m” surely it has to be just that. Not splash proof.

This chart is typical of what you get if you google it. I.e in order to swim in your watch, where it will be less then 1m under the surface, you need a watch that is water resistant to 100m depth.

The charts are nonsense.

[Evanivitch]

You need to appreciate the difference between static and dynamic pressures.

A watch gently submerged into a 50m deep pool may very well be proof at that depth. But the pressure of moving the item quickly through the water, or forcing water at pressure at the item may exceed the pressure seen at depth.

Especially when you consider something like swimming when the device is repeatedly crashed into the surface, when the intention was to be gentle submersion.

[Wills2]

jimmy156 said:

So I had always assumed that the water resistance stated on a watch by the manufacturer was accurate. As such, with my seiko 5 being water resistant to 3bar (30 meters) I have undertaken various activities that don’t exceed submerging it below 30 meters. So it has stayed on for car washing, bathing my son, swimming in pools, swimming in the ocean, paddle boarding, kayaking etc. its 9 years old and works fine.

If pretty much every internet site / forum is to be believed. 3 bar water resistance is only good for leaving your watch on while you wash your hands, and you should try not to get it too wet!

So who is right? The internet / watch forums, or the manufacturer, and why the discrepancy?

Have you not answered your own question with your own experience? The discrepancy is down to people talking rubbish on the internet which flies in the face of the manufacturers claims and your own experience.

[gregs656]

Evanivitch said:

You need to appreciate the difference between static and dynamic pressures.

A watch gently submerged into a 50m deep pool may very well be proof at that depth. But the pressure of moving the item quickly through the water, or forcing water at pressure at the item may exceed the pressure seen at depth.

Especially when you consider something like swimming when the device is repeatedly crashed into the surface, when the intention was to be gentle submersion.

Called it

Care to show your workings on that one?

[Evanivitch]

gregs656 said:

Called it

Care to show your workings on that one?

I take it back, it's your property, equipment qualification tests in UKAS test houses are just for suckers spending public money anyway.

[gregs656]

Evanivitch said:

I take it back, it's your property, equipment qualification tests in UKAS test houses are just for suckers spending public money anyway.

So, no you don't? It's not a question of the testing standard, it's just maths.

[Evanivitch]

gregs656 said:

Evanivitch said:

I take it back, it's your property, equipment qualification tests in UKAS test houses are just for suckers spending public money anyway.

So, no you don't? It's not a question of the testing standard, it's just maths.

You're a project manager, aren't you?

[gregs656]

Evanivitch said:

You're a project manager, aren't you?

Still avoiding the question

Edit: everyone should go and look this up, but dynamic pressure makes bugger all difference to watch sized objects at human speeds. It’s marketing.

Edited by gregs656 on Sunday 31st July 14:41

[Evanivitch]

gregs656 said:

Evanivitch said:

You're a project manager, aren't you?

Still avoiding the question

Edit: everyone should go and look this up, but dynamic pressure makes bugger all difference to watch sized objects at human speeds. It’s marketing.

Edited by gregs656 on Sunday 31st July 14:41

I've given you my response, it's not based on maths, it's based on reality of qualification testing. If everything was proven in maths we wouldn't have qualification test houses to prove it right (or wrong!).

[gregs656]

Evanivitch said:

I've given you my response, it's not based on maths, it's based on reality of qualification testing. If everything was proven in maths we wouldn't have qualification test houses to prove it right (or wrong!).

We know how to calculate dynamic pressure. It’s not difficult - so we can quite easily check if our movement at depth (or at surface level) is going to be higher than the stated depth rating with static pressure.

It’s not going to be. You have to be going either very fast or be very deep, at human speeds and depths nothing you do is going to move the needle.

[troc]

Also, screw-down crowns aren’t for water resistance but to avoid changing settings when underwater.

[trickywoo]

I went to 20m with an old push crown Seiko rated to 50m, it was and still is fine.

I went to about 25m with a 200m rated Seiko SKX007, screw down crown and ISO rated diver. It shat itself.

[Evanivitch]

gregs656 said:

Evanivitch said:

I've given you my response, it's not based on maths, it's based on reality of qualification testing. If everything was proven in maths we wouldn't have qualification test houses to prove it right (or wrong!).

We know how to calculate dynamic pressure. It’s not difficult - so we can quite easily check if our movement at depth (or at surface level) is going to be higher than the stated depth rating with static pressure.

It’s not going to be. You have to be going either very fast or be very deep, at human speeds and depths nothing you do is going to move the needle.

So how do you consider the behaviour of the material in dynamic pressure change in your calculations? How do you calculate for dissimilar materials? How do you make considerations for omnidirectional pressure of submersion versus the point pressures of dynamic movement through a fluid?