Should I get "re-Certified" or take a Refresher scuba course?

[tursiops]

I should have mentioned this in my initial post, I'm definitely planning on getting my own computer. So I guess the edited question is, if I have a computer and know how to use it, is there any reason why I need to know / remember all that other classroom instruction?

If by "all that other classroom instruction" you include safety stuff like what to do if you run out of air or your BCD starts self-inflating, then Yes, you definitely need to know it. I should point out that since you last had that material some best-practices have changed.

 

[caruso]

When I met my girlfriend 7 years ago, she showed me her open water certification from about 20 years earlier. She had only done the checkout dives and got her C-Card which was gathering dust in her attic since then. I got online and purchased gear for her on Ebay, my favorite dive shop, and once she was geared up we headed over to a local beach diving site in Bayville, LI to dive on an old barge wreck in depths up to 30'. She was rather anxious but did fine and halfway through the dive she was digging up clams to use for soup.

We then did a few wreck dive charters off LI and several tropical dive trips, she's amassed over 100 dives to date and got her AOW and Nitrox somewhere in between but there was no other courses or refresher dives other than what we did.

Diving with a trusted buddy with good skills can get it done.

If by "all that other classroom instruction" you include safety stuff like what to do if you run out of air or your BCD starts self-inflating,

I bet most casual vacation divers wouldn't have a clue.

I'm always sharing stuff like that that I'm reminded of by reading ScubaBoard. Sometimes I'll email an article to my group of buddies if it's a good one. Such as "what to do if caught in a downcurrent off a wall".

 

[ScubaTexas]

Agree with all the comments above regarding computers. Arguably, PDCs are more proficient at tracking and planning the real-time information. But, recalling what you know about the tables is always good and may help in a pinch. Knowledge is good and it's something you can easily learn at home. You might find good refresher material on dive tables via YouTube. I suspect the videos will jog your memory and it'll all come back to you. Here are couple I found with a search

 

[JackD342]

With a dive computer, review of tables is optional and up to you. If you want/need a thorough review of the other academics, the PADI eLearning Scuba Review or Reactive are each about $60, and a good way to do so independently and efficiently without a full course.

 

[Esprise Me]

I don't think my OW course really taught us how to use tables. There was a poster with the basic table (not even the back side for repetitive dives) that was gestured at, but we were given a code for a computer simulator and all our dives were done with computers supplied by the shop. I had bought the PADI OW manual with tables on Amazon several months before I signed up for the course and learned how to use the tables, but I wouldn't even have had a copy of them otherwise.

 

[caruso]

I watched the video above and I'm confused, not having done tables in years. Why is the residual Nitrogen time higher when calculating a subsequent dive when you choose a shallower depth from the table rather than a deeper depth?

Edited to add: Never mind I looked it up. Makes sense. Longer times at shallow depths equal shorter times at deeper depths.

 

[tursiops]

I watched the video above and I'm confused, not having done tables in years. Why is the residual Nitrogen time higher when calculating a subsequent dive when you choose a shallower depth from the table rather than a deeper depth?

See post #4.

 

[caruso]

See post #4.

 

[JackD342]

I watched the video above and I'm confused, not having done tables in years. Why is the residual Nitrogen time higher when calculating a subsequent dive when you choose a shallower depth from the table rather than a deeper depth?

Edited to add: Never mind I looked it up. Makes sense. Longer times at shallow depths equal shorter times at deeper depths.

Reviewing the PADI video, it sure doesn't help that he said "residual nitrogen is 11" rather than "residual nitrogen time is 11 minutes."
But to answer your question, the RNT for PG E at 90 feet is 11 minutes at that depth, leaving 14 minutes remaining for Actual Bottom Time at that depth. (Note that 11 + 14 = 25, the NDL for 90 feet.)
At 35 feet the RNT for PG E is 32 minutes, with 173 minutes left for ABT.

Note that he is demonstrating by solely using the front of the slate, and never refers to Table 3 on the back side which makes the relationships more obvious and provides the ABT rather than requiring the diver to do the subtraction to calculate the ABT - a potentially error prone step when using just the front of the slate.

 

[jerrydascorpion]

I carry 2 computers plus a 3rd in my save-a-dive kit so it's probably never going to happen.

I hear Mr. Murphy likes to dive. Sooner or later you may get buddied up with him.