Quiz - Recreational Dive Planner™ - Max Time

A diver exits the water after a dive to 21m/70ft for 31 minutes. The diver reenters the water 49 mi

  • a. Metric 37 minutes - Imperial 40 minutes

  • b. Metric 19 minutes - Imperial 24 minutes

  • c. Metric 18 minutes - Imperial 16 minutes

  • d. Metric 21 minutes - Imperial 22 minutes


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I believe the RDP was 1987-8

Hans Hass DecoBrain 1983
Orca Edge 1984
Orca Skinny Dipper 1987
Orca Delphi 1989
...and the research for the PADI RDP was well before its creation.

Nobody was teaching computers in basic OW class that I know of until SDI started doing it years later. That may have had something to do with the fact that the founder of the company was also the founder and owner of Uwatec computers, but I don't know the details there.
 
My first post certification dives were more than 20 years ago, and it was in Cozumel, where all dives must be led by a DM, and all those dives are multi-level. After the first such dive, I whipped out my tables while sitting on the boat during the surface interval and saw that my dive was far, far off those tables. I was puzzled. How could I plan for the next dive? I looked up and saw that all my fellow divers were looking at me in amusement. One of them said, "It makes a decent frisbee."

I bought my first computer as soon as I got home.

John, I have to laugh. I went through a similar experience as you did and in the same destination - Cozumel. I bought my first computer around dive 20.

The sad point in today's era (even back when I lived in the islands in 2003-2004) people really don't sit down and learn how the computer functions let alone understand the information it is displaying.
 
I meant teaching new divers to use tables instead of computers was the logical business choice for PADI.

Since there are no standards for computer displays and interfaces and since they’re always coming out with new models with new features, it would be impossible for the training materials to keep up.

That may be why PADI has a specialty course for multi-level diving but doesn’t have one for computer diving (though several courses do require computer use).
I think if you'll check you'll find that probably MORE new divers are being trained to use computers than tables....and that is REALLY a business decision. If I'm a LDS, and I train a new diver to use a computer, I might sell that person a computer. The PADI OW class actually allows either tables or computers as a shop/instructor option; whereas SDI offers ONLY computer training. . My impression is that the computer option is far more popular.
 
I meant teaching new divers to use tables instead of computers was the logical business choice for PADI.

Since there are no standards for computer displays and interfaces and since they’re always coming out with new models with new features, it would be impossible for the training materials to keep up.

That may be why PADI has a specialty course for multi-level diving but doesn’t have one for computer diving (though several courses do require computer use).
When I took PADI OW in 2005 it was tables and no mention (that I recall) of computers. We had all analog stuff. When I was assisting OW courses (2012-15) I believe it was all computers unless a student asked about tables. This may have been a gradual change at the shop over those 4 years.
So what time period are you referring to as it being a business decision to teach tables-- perhaps during the time I took the course 15 years ago? Just curious as to when the option to teach either came about and when the majority went with teaching computers? I think the majority teach computers now--so I've been told.
 
?? What I said is almost a direct quote from PADI material. Here is the definition from the manual for the RDP.
View attachment 584881
Perhaps you are talking about today's ambiguity in BT? After all, a dive computer just tells you (typically) how long you spent below (typically) 5 ft or 1 or 2m. We often call that BT, even though it is longer than the traditional definition, but the definition for the RDP is clear.
OK, accepting this definition of bottom time I’ll amend my bottom time post.
Bottom Time
PADI: Surface to surface or to first mandatory safety stop.
BSAC: Surface to 6m or 9m (if deeper deco stop required).
Bottom Time
PADI: Surface to leaving the bottom.
BSAC: Surface to 6m or 9m (if deeper deco stop required).

Now I see a bigger issue. The accent rate.
With the BSAC definition it doesn’t matter if I ascend at 3 or 15m (BSAC’s maximum) a minute, I would still reach 6m at the planned bottom time target.
Using a slower ascent rate than PADI use in their calculations could compromise their validity.

For example, for someone riding the deco line, there would be a 3 minute variation:
* 5 minutes at 3m/min.
* 2 minutes at 9m/min.
 
I was trained with FIPS/CMAS method in the seventies (probably very similar to BSAC). We were given the US Navy tables but trained to use them with two significant modifications with respect to the US Navy manual:
1) ascent speed had to be as slow as possible, specially close to the surface, and in any case never exceeding 10 m/minute, whilst the US Navy manual was prescribing a fixed constant speed of 18m/minute
2) bottom time had to be computed from leaving surface up to when reaching the first deco stop at 6m (or at 9m);
so in case of a slow ascent there is no harm, as the additional time taken is counted as bottom time.

We were also trained to consider standard to make just one dive each 24h. In exceptional cases a second dive was allowed (but strongly discouraged), using US Navy tables for repetitive dives, and with a minimum surface interval of one hour. If the interval was shorter, the rule was to consider directly the sum of the two bottom times, and the max depth of the two dives, actually as it was a single, long dive.
So no degassing at surface was considered. We were told that, due to the distribution of tissues on the human body, after a deep dive with deco (the standard at that time) some tissues were so saturated of Nitrogen at the time of exiting water, that they were still giving Nitrogen to less saturated tissues for several minutes after emerging, hence the quantity of gas dissolved in these slower tissues was actually INCREASING for a short time after emerging. Only after an hour all tissues started to effectively reduce the amount of Nitrogen compared to the moment of emerging. The deco models used at the time (Haldane modified) were not taking into account these effects (tissue-to-tissue transfers), for them the content of nitrogen in each tissue is always decreasing after emerging, hence it was considered unsafe to rely on these deco models for very short surface intervals.
I warmly hope that modern computers take these phenomena in proper account, and are safe for short surface intervals.
 
When I took PADI OW in 2005 it was tables and no mention (that I recall) of computers. We had all analog stuff. When I was assisting OW courses (2012-15) I believe it was all computers unless a student asked about tables. This may have been a gradual change at the shop over those 4 years.
So what time period are you referring to as it being a business decision to teach tables-- perhaps during the time I took the course 15 years ago? Just curious as to when the option to teach either came about and when the majority went with teaching computers? I think the majority teach computers now--so I've been told.

I took PADI OW in 2002. It was all tables. After a long break from diving, I took NAUI OW in 2017. It was all tables, too.

When I took the PADI divemaster exam four months ago, there were table questions and eRDP questions, but no computer questions.

The information posted by Tursiops about instructors having a choice is news to me—very encouraging news.

Has anyone here reviewed PADI’s new latest-and-greatest e-learning system to see how it handles it?
 
Mike1967–

I don’t know.

Just received 2nd quarter 2020 edition of PADI’s “Undersea Journal” magazine.

There’s an article in it touting its “new Open Water Diver eLearning program,” which is purportedly better than ever.

The article doesn’t describe content changes, so I don’t know whether the improvements go beyond processing and delivery.

That’s why I asked.
 

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