# Dive Watch Bezels



## ESL (Jan 27, 2004)

Why do dive watch bezels count up, instead of down?









To my mind, if you have say 30 minutes of "down time" you should set the 30 minute mark at the current position of the minute hand, and have it count down to zero at the zero "pip" on the bezel.

I don't understand the convention of counting up to 30 (or whatever) , perhaps some of the real (as opposed to desk) divers on the forum can enlighten me please


















In a similar vein, why do "Pepsi" and other part coloured bezels, have the first 15 (or 20) minutes in a contrasting colour or pattern, as opposed to the final 15 (or 20)? Again - this seems to be incorrect logic. Surely it's the final minutes of the dive period that are important, not the first
















What point am I missing...

Yours

Confused, Hertfordshire.


----------



## jasonm (Nov 22, 2003)

The important thing is what your dive time has actually been, not what you think it is going to be, the variable is the air available to you







You cant really know what your 'down time' will be ( why limit it?)

Whilst knowing the dive duration is good practice, its really only essential for planning repetative dives for the same day, these dives are planned using first ( and other ) dive depth and duration, surface interval between dives.


----------



## jasonm (Nov 22, 2003)

The bi-coloured bezels are for timing a 20 min period of your dive, in theory, 20 mins ( The red part) is the max time you can stay at 30m without going into a decompresion situation, again this is a bit misleading as no one in practice will plummit to 30m and stay exactly there, a dive is all about give and take with trading time for depth and vice versa, it all varies with your particular dive profile, dive bezels are a great back up and for rough calculations , but modern dive computors worth out everything for you ....Thank god, dive table calculations never came easy to me









Here is one side of the dive table,


----------



## pg tips (May 16, 2003)

some more "enlightend" manufactures bucked the convention although it could be argued they knew little about what a diver wanted from a watch









watch on left not my watch pic off net without permission


----------



## ESL (Jan 27, 2004)

Thanks Jase: that is clearer now. I had incorrectly assumed that the air in the tanks would have been more or less a constant. Of course, it can't be as the depth of the dive and the amount of effort the diver is expending will vary the amount air consumed.

I also had not clicked that the first 20 minutes was linked to ND limits - but now you mention it, that makes perfect sense too.










I consider myself enlightned.










Mind you PG, It does make you think that perhaps Timex (et al) perhaps did not know what the were really doing









I used to have one like that one on the right, black bezel though. Good lord - must have been about 1975 or something like that...


----------



## PhilM (Nov 5, 2004)

Another couple of great Timex's PG











ESL said:


> I used to have one like that one on the right, black bezel though. Good lord - must have been about 1975 or something like that...


Me to here's mine I found it finally at Christmas after loosing it at my parents about 15 years ago


















As for those charts Jason I havent a clue


----------



## ESL (Jan 27, 2004)

You'll have to join the "No really, I haven't a clue" Club then Phil. We don't seem to had had any new members for a while.









Ask Mac about membership details;


----------



## jasonm (Nov 22, 2003)

Yep, I think you have just been conscripted Phil









Reprt to Major Mac for assimilation.......


----------



## PhilM (Nov 5, 2004)

ESL said:


> You'll have to join the "No really, I haven't a clue" Club then Phil. We don't seem to had had any new members for a while.
> 
> 
> 
> ...


Is this a good thing


----------



## mach 0.0013137 (Jan 10, 2005)

PhilM said:


> ESL said:
> 
> 
> > You'll have to join the "No really, I haven't a clue" Club then Phil. We don't seem to had had any new members for a while.
> ...


But of course, it`s an honor & a privilege









You have already fullfilled the membership requirements and therefore, on behalf of the club, I am pleased to offer you full membership, if you wish to join please add the clubs name to your signature









You will be pleased to learn in the present hot weather that the initiation requires that your significant other throws buckets of cold water over you whilest dressed in suitable swimwear









BTW George good questions, I`d wondered the same things myself


----------



## Olive Drab (Sep 11, 2005)

jasonm said:


> The bi-coloured bezels are for timing a 20 min period of your dive, in theory, 20 mins ( The red part) is the max time you can stay at 30m without going into a decompresion situation, again this is a bit misleading as no one in practice will plummit to 30m and stay exactly there, a dive is all about give and take with trading time for depth and vice versa, it all varies with your particular dive profile, dive bezels are a great back up and for rough calculations , but modern dive computors worth out everything for you ....Thank god, dive table calculations never came easy to me
> 
> 
> 
> ...


thanks for reminding me to get out my tables and start practicing again. been a while since i went diving and im starting to forget things.


----------



## Chromejob (Jul 28, 2006)

Interesting reading.... Jason, I'll bet I could figure this out with your table, but you may know the answer "on autopilot."

My Seiko H558-5000 has a middle dial with numbers which I've never grokked. Here's a good illustration:

http://www.pbase.com/elveez/image/50790909

Note that at the six o'clock position it's labeled "Depth Meter." Is it related to down time, or just another dial that the bezel index pointer can mark?


----------



## PhilM (Nov 5, 2004)

Just to put something else to this thread







I'm currently wearing my RLT20 today and wanted to time something earlier so set the bezel and noticed that it's got a completely different configuration to any of the other watches that we have been discussing in this thread


















Just goes to show that you can't beat a bit of genuine


----------



## Ironpants (Jul 1, 2005)

PhilM said:


> Just to put something else to this thread
> 
> 
> 
> ...


Whose colours are those on the strap Phil?

Toby


----------



## PhilM (Nov 5, 2004)

Ironpants said:


> PhilM said:
> 
> 
> > Just to put something else to this thread
> ...


Red Blue and Grey









No it's a speed bird strap


----------



## Ironpants (Jul 1, 2005)

PhilM said:


> Red Blue and Grey
> 
> 
> 
> ...


You see I thought it was a regimental strap







and I would have to find some connection via family or friends to justify wearing it, because it does look good on the 20 

Can I order one without worrying then







?

Toby


----------



## PhilM (Nov 5, 2004)

Go for it Toby will be glad to have you in my gang


----------

