RDP wheel, a dying art?

[macgyver2258]

I have recently finished my Rescue class and Nitrox(PADI) and was wondering about the dive wheel. I only used it in my OW cert class and have never seen anyone use it while diving. From what I hear the cost for it is about $45US. Is it a dying art, like stained-glass? Or is it that you scrape up some more money and can buy a cheap dive computer? I understand its’ purpose but I don’t see where it fits into diving. Please shed some light on the idea.

 

[Henryville]

I have recently finished my Rescue class and Nitrox(PADI) and was wondering about the dive wheel. I only used it in my OW cert class and have never seen anyone use it while diving. From what I hear the cost for it is about $45US. Is it a dying art, like stained-glass? Or is it that you scrape up some more money and can buy a cheap dive computer? I understand its’ purpose but I don’t see where it fits into diving. Please shed some light on the idea.

If you want to get a professional certification from PADI, you will use it again to pass your exams in DM and OWSI. Beyond that, it is a very good idea to use tables as a check on your computer for dive planning (e.g. know roughly where you ought to be at a given profile to stay out of deco. The wheel as you know is a refined table that takes out some of the rounding and allows multi-level planning. You could use it for that.

I bought my wheel in 1989 or 1990, I think that was right after they first came out. Bottom line, the only time I have used it in the last five years, and the only time I have seen it being used, was for the advanced PADI classes.

 

[ShakaZulu]

I have recently finished my Rescue class and Nitrox(PADI) and was wondering about the dive wheel. I only used it in my OW cert class and have never seen anyone use it while diving. From what I hear the cost for it is about $45US. Is it a dying art, like stained-glass? Or is it that you scrape up some more money and can buy a cheap dive computer? I understand its’ purpose but I don’t see where it fits into diving. Please shed some light on the idea.

The wheel is used for multi-level diving and is much simpler to use than the tables.

 

[DandyDon]

Yeah, the wheel can be used to plan a multi-level dive in detail, probalby more detail than you'd really want to plan.

In reality, many divers plan the bottom time on their computers, then use them to actually track their N2 load for the dive.

Pelagic computers - like Oceanic and Aires - track N2 loading about like the Padi tables, although their tables are modified. Some other brands are "more conservative," meaning that they deny you bottom time that Padi tables would allow.

I'll dive my Oceanics to the NDL, but then do deep and shallow stops to get back into the Green (safer) area. Some divers leave the water in the Yellow, thinking that Not-Red is enough, but Yellow is Caution!

 

[macgyver2258]

Thank you for your replies. I dive with an Oceanic DataMax while my buddy uses the Uwatec Smart COM. It is amazing how much extra time I get for bottom time. I think he also has a conserve-ability setting he can adjust but doesn't know how. But I'm happy to follow the more conservative comp. But for the wheel I just wonder why don't they include that in class kit and just teach us that. Almost all of my dives are multi-level dives, except for the boat dives. I agree its not hard to use, once you grasp the concept, but is PADI afraid to scare off mathematically challenged people? I would also like to note that everyone should learn the tables, for this is the basis of the wheel, computer, etc. Do other cert agencies use a wheel or just tables? Thanks for you input in advance.

 

[Scuba_Steve]

I have recently finished my Rescue class and Nitrox(PADI) and was wondering about the dive wheel. I only used it in my OW cert class and have never seen anyone use it while diving. From what I hear the cost for it is about $45US. Is it a dying art, like stained-glass? Or is it that you scrape up some more money and can buy a cheap dive computer? I understand its’ purpose but I don’t see where it fits into diving. Please shed some light on the idea.

Hi gents:

I used it once, in my PADI DM class. Unfortunately, as Henryville says, I will have to endure it again in an OWSI class, if I decide to continue on in that direction.

I'm not sure why it is so tabboo to speak about it, but GUE has a very simple way of determining your NDL limits, with air or Nitrox. ou can even run multilevel and multi-dive days with it as well.

It doesn't require huge amounts of math, or spinning a useless (And WAY OVERPRICED) P.O.S. wheel.

Assuming your head stays attached to your body, you'll never forget to bring it, worry about it breaking, getting wet or bending it in your gear-bag. (Pardon the pun) Also you'll be the talk of the party with your dive friends when you can figure out within a minute (if it takes you that long), your NDL for a couple dives back to back, faster than they can say R.A.T. (Think about it, it'll come to you).

The best part is, you can get the info, with a small amount of mining, right here on ScubaBoard,....for free!!! And you don't even have to enroll in a GUE course.

*WARNING* After seeing the no-nonsense way of doing it, you may find yourself thinking these guys have got it together and may be persuaded to get the real McCoy by taking their courses.

*Reality check* I've never taken a GUE course to date, so I wouldn't be listening to me if I were you

Try some dry-runs using your table or over-priced-wheel and see for yourself!

It really does work! Imagine that!.

Regards folks

Steve

 

[DandyDon]

INteresting response. I gotta' break this down... :colgate:

Thank you for your replies. I dive with an Oceanic DataMax

I like the Pelagic approach - giving you more bottom time - similar to Padi's - than the "more convservative," then allowing you to regain safety with extended stops back into the Green Zone.

while my buddy uses the Uwatec Smart COM. It is amazing how much extra time I get for bottom time.

IN other words, his is more conservative by penalizing, offering less than Padi.

I think he also has a conserve-ability setting he can adjust but doesn't know how.

All too common. IMHO, a computer owner who does not fully understand how the machine works, with the ability and common practice of running Simulations should not be in the water with the computer.

But I'm happy to follow the more conservative comp.

Oka-a-ay

But for the wheel I just wonder why don't they include that in class kit and just teach us that.

It'd run the cost of the package up, and the classroom as well, making them less competitive.

Almost all of my dives are multi-level dives, except for the boat dives. I agree its not hard to use, once you grasp the concept, but is PADI afraid to scare off mathematically challenged people?

That, too. You can plan the same dives the same way nearly with a regular chart. Just use zero surfect intervals.

I would also like to note that everyone should learn the tables, for this is the basis of the wheel, computer, etc. Do other cert agencies use a wheel or just tables? Thanks for you input in advance.

.None that I know of.

*Reality check* I've never taken a GUE course to date, so I wouldn't be listening to me if I were you

I know very little about GUE or DIR, but undertand they're totally different from Padi.

 

[Charlie99]

I like the Pelagic approach - giving you more bottom time - similar to Padi's - than the "more convservative," then allowing you to regain safety with extended stops back into the Green Zone.

I'm sure you realize it Don, but although the Pelagics use the same model as the PADI RDP and wheel, in the real world, dives are more likely to be at the limit of the model when using the computer. This is because divers calculate on the RDP as if the dive is square profile, but then actually dive to less than the max table depth for much of the dive. Even with the wheel, there is a lot of conservatism built into the typical dive profile because you aren't always right at the max depth of each step. A prudent diver will do as you suggest and tailor there profile such that you have a bit of extra margin as calculated by the computer.


As far as use of the wheel, I find it awkward to carry. I do use a flat table equivalent of the wheel for planning multilevel dives. The table uses the DSAT/Spencer M-values, but differs from the PADI wheel/RPD by +/-1 minute here and there.

 

[The Kraken]

I have a wheel in my dive log along with the tables for air, EAN32 and EAN36.

I always use it to plan a dive and transcribe the dive plan onto my slate.

When doing a nitrox dive I will plan my dive on the percentage of oxygen indicated by the analyzer when I check my tank/s.

I have a calculator that I keep in my dive log with several fomulae resident in its memory. One formula is the conversion to generate an Equivalent Air Depth based upon the percentage of oxygen in my nitrox mix.

You can use the wheel to plan nitrox dives if you can do the EAD conversion.

An added benefit is that you can plan dives in 5 foot increments.

 

[Jim Baldwin]

I have recently finished my Rescue class and Nitrox(PADI) and was wondering about the dive wheel. I only used it in my OW cert class and have never seen anyone use it while diving. From what I hear the cost for it is about $45US. Is it a dying art, like stained-glass? Or is it that you scrape up some more money and can buy a cheap dive computer? I understand its’ purpose but I don’t see where it fits into diving. Please shed some light on the idea.

Each quarter I teach an advanced class at the local university. We have classroom one night and pool one night a week for 12 weeks. Since I have additional time I usually devote one classroom to using the wheel.

The students like it and yes we show the advantages of using various dive computers but for $45 you extend your bottom time using the multilevel formula. And besides most college students don't have the extra cash to drop on new gear and computers.

Jim
Louisiana