Any experiences with SOS talismans and diving?

[LarsB]

Dear divers,

the manufacturer of the SOS talismans (http://www.sostalisman.com/) says they have supplied some to members of the BSAC, who use them for diving.

What are your experiences, are they really watertight, up to which depth, or how does the paper react when it gets wet from (salty!) sea water, and how well do the talismans resist corrosion from sea water?

Which material is best, stainless steel, chrome-plated, gold-plated, or titanium?

Also in terms of allergic reactions, e.g. to nickel etc.?

Thank you very much for any reports and hints!

Cheers,
Lars

[LarsB]

According to this source (http://www.amazon.co.uk/SOS-Talisman-SOS-Talisman-Capsule-Titan/dp/B001HMS82C) ("is water-proof up to 3 bar and is fire resistent up to 600°C"), they are tested with 3 bar, so they should be ok till a depth of 20 m.

But what are your actual experiences?

I have one SOS talisman (stainless steel) which is about 30 years old (I got it when I was a child); I put it into a glass of water for 24 hours before yesterday, and it obviously leaks a bit: the paper inside became moist (not wet, but clearly moist).

Probably the O-ring inside of it should be replaced, but I still wonder...

[Mike Halligan]

According to this source (http://www.amazon.co.uk/SOS-Talisman-SOS-Talisman-Capsule-Titan/dp/B001HMS82C) ("is water-proof up to 3 bar and is fire resistent up to 600°C"), they are tested with 3 bar, so they should be ok till a depth of 20 m.

But what are your actual experiences?

I have one SOS talisman (stainless steel) which is about 30 years old (I got it when I was a child); I put it into a glass of water for 24 hours before yesterday, and it obviously leaks a bit: the paper inside became moist (not wet, but clearly moist).

Probably the O-ring inside of it should be replaced, but I still wonder...
I've no experience to relate, but I'd be careful how I interpret the claim "waterproof to 3 bar". If true, this is likely to be static load of 3 bar and I'd relate that to a dynamic load when diving of about one third, or 1 bar.

At a guess, this would be a pressure differential between inside (1 bar) and out (2 bar) at 10m.

A physicist will be along shortly to correct me. :D

[LarsB]

Dear Mike,

thanks a lot for drawing my attention to this point!

Of course you are right, dynamic pressure could be much higher than the (most likely) static pressure used for the test.

However, I wonder, when wearing it around my neck, under my diving suit (sometimes even under an additional T-shirt), whether such high dynamic pressure peaks would actually occur or play any significant role.

On the other hand side, wearing it with a bracelet around your wrist might, on the contrary, expose it to high dynamic pressure peaks due to sometimes brisk hand and arm movements.

[Nigel Hewitt]

Of course you are right, dynamic pressure could be much higher than the (most likely) static pressure used for the test.
Grief not this old chesnut again. :o

The dynamic pressures on divers and diving equipment are trivial.
This myth came about because people wondered why watches are rated to hundreds of meters deep and yet leak at the first opertunity.
Nobody wanted to admit that a watch maker test is rigged so any old junk will pass.

If I was to strap a watch or a talisman to the bottom of my foot and stride in off a reasonably high jetty it would only suffer a small fraction of a bar of over-pressure.

A very small fraction.

How do I know? Well I notice that my legs don't break off. :eek:

Half a bar on the bottom of my foot would be well over 150Kgs load.

[TerryH]

Save your dosh.

Draw a rectangle on word and split it into two. You'll need to play with
sizes, because you only have about 40mm square to play with.

Type all your details and medical stuff. As it's typed it's clear and the
point size can be small, so you'll get a LOT of info on this.

Print, cut the whole lot up and fold down the middle. Bit of spray-mount
or simple paper glue will do.

You've now got a square of about 200gsm card, with text both sides.
Now laminate using a small credit card pouch, but stick it at one end.

Punch single hole in clear end making sure that the pocket with the paper
isnt breached.

Stick some cord on it and hang round your neck :D

The best bit with this is you can stick MEDICAL ALERT in big red letters
etc. I've used these for labling BC's etc and they've been to 50m pinned
to regs and BC's etc. with no probs.

Best bit is you dont need to stop with one. You can stick them everywhere.

[LarsB]

Excellent alternative/idea!
Thank you!

[Mike Halligan]

Grief not this old chesnut again. :o

The dynamic pressures on divers and diving equipment are trivial.
This myth came about because people wondered why watches are rated to hundreds of meters deep and yet leak at the first opertunity.

:o Thanks, Nigel! :cool:

[Luke Hickton]

Great alternative from TerryH. Might be quicker/easier when using MS Word to create a table (2 columns, 1 Row) and in the table properties set it to the size you require. In this example 4cm x 4cm.

Saves time/paper in the trial and error phase.

[Helen (AKA Hellvet)]

or try medic alert bracelets - they work well at depth - had one for 4 years and as its metal not really affected by diving, no rust either... they will provide up to date medical info, and details of doctors, treatments and meds from all over the world.

They do charge me £20 a year but i feel its worth it! They've replaced the bracelet when i managed to break it on a door(don't ask) at no charge and also give you a laminated card for your purse/wallet, which they replace yearly after checking for any changes/updates, and free of charge through the year.