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Old 13 April 2024, 05:15 PM   #65
ts3
"TRF" Member
 
Join Date: Nov 2018
Location: Europe
Posts: 3,262
Quote:
Originally Posted by l_chissle View Post
Well 30m of true diving I think is > 120m of static pressure.
Your thinking is not correct...

TLDR Static pressure is all that matters when you are diving or swimming. Different story if you fall off a speed boat or jet ski.

Static pressure is rho x g x h, dynamic pressure is rho /2 x v^2 and I didn't get my PhD in physics to remember that... LOL

For dynamic pressure equivalent to the static pressure at h = 30m depth you'd need to move your hands at nearly 25m/s or 90 km/h in the water. Try to do that as a human being in water... Different story if you fall off a speed boat or jet ski but then you'll have other problems. But I'd not use a 30m rated Patek on a jet ski. For dynamic pressure equivalent to the static pressure at h = 120m depth the required speed increases to around 50m/s or 180 km/h. Of course you need to add static and dynamic pressure to arrive at the total pressure you'll need to compare with the rating of your watch.

I have been using my 5711 swimming, free diving (won't get lower than 10m depth), and paddling all the time and I have been doing the same with my 60m rated IWC Mark XV for 20+ years no problem.
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