Help! The PADI wheel...

[Jim Lapenta]

I'll have to sit down and play with the rdp for a bit but yes you can do multilevel profiles with it. you just add your time at each depth to the time in your ending pressure group for the previous depth. ie 70' for 15 min gives pressure group E, next depth 50 ft for 22 min. follow E to 50 ft depth, which is 21 min add the 22 min gives you 43 min which is pressure group N, next depth 35 ft for 30 min follow pressure group N to 35 ft depth shows 73 min add the 30 min actual time gives 103 min rounds up to 108 ans is pressure group S. Just verified this with both table and wheel. You can also use erdp for this in dive planning mode just insert 1 minute for surface interval when asked. If you are conservative anyway this 2 min for a 3 depth dive will not be a problem. You can see one of my earlier posts for the specific steps for using the erdp. I'm to tired to find it and post a link to it here. Jim

 

[lostplanetairman]

When I was in highschool we had slide rules (calculators were big bucks). When I started flying, several decades ago, we had a wheel thingee to calculate ground speed, wind angle etc ( don't ask, I don't remember,we don't use those things). Ah, back to the wheel, when I was introduced to it as a DMC, I was at first fearful and then upon further study, it did seem to work okay. That of course was after an afternoon with the bugger and the Manual (a must have). What I noticed was, just like a slide rule there were inaccuracies caused by the lines not lining up caused by you or the wheel were tilted. Conclusion IMHO, good for diving, not so good for taking tests, better than the RDP, and good to know how to use. Personally I use 2 computers and dive planning software but still practice with the tables. Wish me luck.

 

[Double_D]

Roatanman is dead on target. What he said. Sometimes the shortcuts don't really save anyone much time.

You gotta swim to earn your fins. You gotta learn to work long division by hand before you get to use your calculator in class. And you oughta learn the tables before you dive with a computer. I'm a firm believer in learning how to drive the standard before you get an automatic.

Bubblzmaker, my best recommendation to you is the video. Sure it's overacted but it's also very thorough. Get it and watch it. Twenty minutes and you'll be proficient again.

I carry an RDP in my BC pocket all the time - for close encounters. In the highly unlikely event my electronic computer fails at depth, my watch and my RDP will guide the other big dive computer in my skull and get me back to safety. You're not really lost if you know where you are.

 

[Charlie99]

I'll have to sit down and play with the rdp for a bit but yes you can do multilevel profiles with it. you just add your time at each depth to the time in your ending pressure group for the previous depth. ie 70' for 15 min gives pressure group E, next depth 50 ft for 22 min. follow E to 50 ft depth, which is 21 min add the 22 min gives you 43 min which is pressure group N, next depth 35 ft for 30 min follow pressure group N to 35 ft depth shows 73 min add the 30 min actual time gives 103 min rounds up to 108 ans is pressure group S. Just verified this with both table and wheel.

To truly emulate the wheel when using the RDP or ERDP is this manner, you also need to take into account the wheel's ML (Multilevel Limits -- kind of a reduced NDL for multilevel profiles), and the restrictions on allowable combinations of depths, as well as the rules in the wheel handbook (most of which are commonsense rules along the lines of "all time gets counted as at the deeper level until you have ascended to the next level", and "if you redescend, then all the time has to considered as being at the deeper level".)
ML's and depth combo restrictions are listed on my Flat table equivalent of the wheel

 

[Dan Gibson]

OK, so I wasn't imagining it. There is a way to use the tables like the wheel, although it sounds like a royal PITA.

To truly emulate the wheel when using the RDP or ERDP is this manner, you also need to take into account the wheel's ML (Multilevel Limits -- kind of a reduced NDL for multilevel profiles), and the restrictions on allowable combinations of depths, as well as the rules in the wheel handbook (most of which are commonsense rules along the lines of "all time gets counted as at the deeper level until you have ascended to the next level", and "if you redescend, then all the time has to considered as being at the deeper level".)
ML's and depth combo restrictions are listed on my Flat table equivalent of the wheel