Padi Tables and Cold Water

[DA Aquamaster]

When I took my OW and AOW in 1985, we used the older PADI table that was essentially a rebranded US Navy table. The US Navy table is very liberal by modern standards and was not really intended to be used for repetetive diving in US Navy service so it was common to round "up" to the next greatest time and next greatest depth. You also planned the deco/NDL limits using square profiles at the deepest depth while religeously avoiding actually diving a square profile at that depth in order to create a healthy fudge factor.

For a cold water dive or strenous dive, we were taught to round up to the next greatest depth and for a strenuous dive in cold water we were instructed to round up to the next greatest depth AND time.

Newer tables are more conservative, but it is still prudent to round to the next greatest depth to accommodate the potential for reduces circulation and offgassing in colder water. And I'd define a "cold water" dive as any dive where you get at all chilled.

 

[Ber Rabbit]

Actually round up a letter will always be more conservative to adding 10 ft.

I just ran a couple of quick figures through my NAUI table before I posted and ended up with the same result doing both methods. I didn't have time to search for combinations that would not work.
Ber :lilbunny:

 

[BuoyantC]

Anytime you feel cold, even on just hands and face, your body is already working on some vaso-constriction. Since this progresses throughout the dive, think of it as nitrogen entering the tissues on a superhighway but on a country lane coming out. That's one of the reasons for the extra safety margin.

So, taking the next depth range, or higher pressure group letter for dive planning always makes good sense. Now if you are only working the tables AFTER the dive..........!

Good question though,

Dennis