Found out our dive tables are based on 1950s Navy data that didn't account for cold water

I was reading through the US Navy Diving Manual revision notes last night and saw that the original no-decompression limits were derived from warm water trials in the Pacific, so those 3 extra minutes I gave myself on a 100 foot wreck in 48 degree Puget Sound water might be exactly the wrong call, anyone else adjusting their bottom times for temperature now?

2 comments

2 Comments

the_jordan22d ago

Damn, that's wild. It's like those old food safety rules from decades ago that we still follow even though we know better now. Like how people used to think you had to wait an hour after eating before swimming, or how we all grew up thinking breakfast was the most important meal of the day. The info gets passed down and we just trust it because it's what we got taught. Same with dive tables, nobody rechecks the math until someone gets hurt or a computer shows them something different. It makes you wonder what other common sense stuff we're all following that's secretly outdated.

williams.jenny22d ago

You ever done a dive where you felt fine but your computer was screaming at you for no reason? I hit the same wall in the Great Lakes last fall. Water was 44 degrees at 90 feet, and I cut my bottom time by 8 minutes from what the tables said. Just felt wrong to trust warm water math when my fingers were going numb. Now I treat cold water like a whole different ballgame. I set my personal limit 10 minutes under the table number, no exceptions. Better to surface early and bored than late and bent.