Quiz - Recreational Dive Planner™ - Max Time

[TMHeimer]

I would bet 99% of people who were taught how to do tables in their OW classes could not do them now.

Yes. Unfortunately that also is probably a reason for review.

 

[scubadada]

I am not sure what you mean by this. I need a little more information to fill in my blanks.

According to The DSAT Recreational Dive Planner: Development and validation of no-stop decompression procedures for recreational diving. (February 28 1994), by R.W. Hamilton, Raymond E. Rogers, Michael R. Powell, and Richard D. Vann, multi-level diving was a primary goal for the RDP research from the start.

And it was rapidly developed as the DSAT computer deco algorithm

 

[scubadada]

Yes. Unfortunately that also is probably a reason for review.

But to answer @Pedro Burrito quiz questions is

 

[txgoose]

I love the knowledge base on this board.

 

[boulderjohn]

I understand the concept of surfGF: the gradient factor you would have if you surfaced now.

But how do people manage this during an actual dive ?

Do you try to stay longer to bring it down on the last stop for example ?

Is it more useful than extra time against your schedule because it is measured in GF ?

Think of it this way. The safety stop's purpose is to bring your SurfGF down from Point A (whatever it might be when you reach 15 feet) to Point B (whatever it is after 3 minutes at 15 feet), with the assumption that if the SurfGF at point A was marginally safe, then whatever it got to 3 minutes later was likely to be fully safe.

The SurfGF feature on a computer allows you to do that with much better precision. When you reach 15 feet, you look at it and see where it is. You then wait until it gives you a number you like, whatever amount of time it takes. Let's say you arrive at that depth with a SurfGF of 80. You might decide you want to hang around until it gets below 70. Or 65. Or whatever. That becomes the time you begin your ascent, regardless of how much time you were at the stop, not an arbitrary 3 minutes.

Do what I just described for a few dives and see how you feel about a 3 minute stop when you arrive at 15 feet with your SurfGF already at 45.

 

[Mike1967]

Or whatever.

So what is your target, is it a percentage below your GF high setting?

 

[tursiops]

According to The DSAT Recreational Dive Planner: Development and validation of no-stop decompression procedures for recreational diving. (February 28 1994), by R.W. Hamilton, Raymond E. Rogers, Michael R. Powell, and Richard D. Vann, multi-level diving was a primary goal for the RDP research from the start.

This is true. But that desire was not embedded in the RDP table. Later on, it became part of the Wheel, which cost more, was complicated to use, and apparently nobody but professionals and serious diver-nerds ever bought one. Duis (1991) wondered if there was a way using only the info on the RDP table to safely plan a multilevel dive, presumably one that matched or was even "safer" than the Wheel. that is what he reported. It is possible. I even have marks on one of my RDP tables to allow me to do it. then the Wheel info was embedded in the eRDPml, which avoided the analog ambiguities of the Wheel and was easy to use. Of course, it was a decade too late to have any impact....

Does that help?

 

[scubadada]

So what is your target, is it a percentage below your GF high setting?

So, I will give this a shot. I dive at GF high of 95 to reasonably match my DSAT. I run my SurfGF down to the mid to high 80s before I surface. This only comes into play when I have closely approached no NDL

 

[Mike1967]

This only comes into play when I have closely approached no NDL

So if you're already under your target SurfGF you don't stop?

 

[scubadada]

So if you're already under your target SurfGF you don't stop?

No, I do a 3 min stop, regardless. Seems like no stop would be fine.