REALLY REALLY technical question.
 

1) Say my Subbie goes to it's limit under water, 1000'. How many pounds per sq. inch of water pressure are at that depth?

2) And the Seadweller has it's helium gas escape valve, but remembering my dive master, and chemistry class, helium molecules are extreemly small. I have heard reports of lessor watch's crystals popping off on the ascent to the boat. So does helium actually enter a watch, in the water, and could it pop my crystal since it does not have an escape valve like the Seadweller?

3) Lastly, with the three seals in the crown and tube, if my Subbie's crown is fully unscrewed without the stem pulled out, is there any water protection afforded at this point at all? or is it :bye: movement?

Just wondering.

1. Don't know.
2. I think I've explained this before that the Helium valve is for professionals who go underwater in a bathyscape or a submersible. The air they breathe is oxygen and other inert gases, He being a large constitutent. These He molecules are very, very micoscopic and can enter the watch thereby creating an internal pressuer which can pop the crystal.
That's when the He valve comes into place and automatically releases the excess gas and thus the pressure.
3. Even with the crown unscrewed, guys have gone swimming with no disastrous effects. The stem is surrounded by waterproof gasket seals which afford a relatively good degree of protection. However, for very deep sea diving, it is recommended that the crown be full screwed in. I don't think the gaskets surrounding the stem could withstand those high pressures.

JJ

The answer to your first question depends on whether you are in salt water for fresh water.

PSI can be approximated by using the following formulas:

Salt water..... psi = depth * 0.445 (or in this case 445 psi)

Fresh water.... psi = depth * 0.432 (or in this case 432 psi)

You really should add atmospheric pressure to this though so you would be at 459.7 psi for salt water and 446.7 psi for fresh water.

The area of a crstal is very close to 1 square inch (1.09). If we take the area the force is exerted over, we find that just over 500 pounds of force are exerted on the crystal at 1000 feet.

Anyone wanna double check my math and formulas, it's been a few years since I've been in school. Thanks!

My little handheld calculator came up with 501.+ so your 500 pounds estimate was certainly close enough for govt. work, Seth. :thumbsup: :thumbsup:

That's pretty generic, Seth. Could you tighten that up a little bit :rofl: :rofl: :rofl: :justkiddi Great answer, dude :thumbsup:

Any volunteers to load 500 pounds of steel on sub's crystal on gym? :agree: I can come and take a pic :agree:

By the way, this is a bit OT but...

Any experience or real life investigations how these divers' watches keep their water resistance in practice? I assume subs and seamasters can be well used for swimming :agree: but how about going deeper? Lets say scuba diving or freediving (some disciplines close to -200m).

Or taking those to sauna..? :agree:

Good question!! Same principle as the hatch of a real Submarine. The greater the depth, the greater the pressure and hence the sealing pressure applied on the caseback and crystal of the watch.

JJ

Thanks everyone, I know it was a strange question, but i was watching a
re-run on the Discovery Channel about the unbelievably beautiful girl, Tanya Streeter (totally HOT!) that has the womens record for free-diving. I want to say in excess of 370 ft. No scuba, no air, nothing but flippers. She is able to hold her breath for up to 6 Minutes!! And having passed my advanced cert. with PADI, I took my Subbie Date down to 120 ft. for my decompression dive on a wreck in the Keys. So, i was just wondering what my poor Subbie goes thru at 1000 ft., not that I'll ever see 1000 feet.
Sadly, Tanya does not wear a Rolex, It looked like that TAG Professional diving watch to me (it's bigger than she is!). Which brings me to another point, she is EXACTLY who Rolex should sign up, not another 50 y.o. opera singer! I had stated in another thread that they need to get more contemporary spokes-people like Maria Sharapova, and this girl Tanya Streeter, two stunning blondes. Because, I do not see the 20 somethings embracing fine watches like our generation does. But that's another thread for another time.
Google Tanya Streeter to see her pics if you want, or maybe JJ can upload a few for us, I'm too lazy (Okay, I don't know how), and thanks all for answering my questions!:clap:

David

You mean this one? :chuckle:
http://i6.photobucket.com/albums/y20...lamourShot.jpg

Same person. http://www.redefineyourlimits.com/

Well David flippers,the term is surely fins.
.