Help with RDP Question please !

[Diver0001]

Am I right in thinking here that if the residual nitrogen level added to the bottom time puts you in the black when you calculate the next depth then you should use a more conservative figure? As that obviously makes the answer above wrong. As the second dive puts you in the black...

Thanks for everyones help.

tris

p.s this question comes from the instructor candidate workbook. There are no answers accompanying it.

..... unless you mean the thing about surface intervals in the W to Z range...... In that case the 2nd surface interval would need to be 1 hour instead of 12 min. If you were following this rule you'd end up with answer of 240 min..... The version of the RDP I have doesn't stipulate this but I think the newer versions do..... I'll edit my original answer to reflect this.....

R..

 

[Don Burke]

To be honest im using a RDP printed on the back of my log book so it may not be that reliable !! Anyhow - thanks so much for you time and effort.

tristan

How does it check against the tables here?
http://www.diversresource.com/resources/divetables/

 

[OneBrightGator]

If this is a PADI test question it could be tricky. PADI's definition is that bottom time for calculation purposes stops as soon as the ascent starts and you do not include safety stop time.

I always count my time from descent to surface, no need to cut corners here. But if it is a test question watch out for that little trick.

Mike

Mike, the question is asking for total runtime, excluding ascent time (including descent time because it's included in bottom time).

Diver0001... very nice job

Ben

 

[Diver0001]

You know, I was thinking about this problem again. If you wanted to do the dives as FAST as possible you could do this:

Dive #1 - Multilevel 30m/19min followed by 10m/90min. You know you can do this as a multilevel profile because you would be an M after the first part and you needed to be a T to do the second part.....

And Dive #2 16m/42min

In that case you would be W coming out of the first dive which requires a 60min SI but it just happens to be exacly what you need to make dive #2.

So your total runtime would be

Dive#1 - 90+19+3+60
Dive#2 - 42+3

The total run time is now 214 instead of 237.

It does introduce a reverse profile of less than 40ft, which according to recent research doens't carry a significantly larger DCS risk and you create a little gas management issue during the first dive. In my case I would have to do the first dive with a twin-15 (double 104). In reality even though it fits in the tables I wouldn't recommend it.

R..

 

[pt40fathoms]

You know, I was thinking about this problem again. If you wanted to do the dives as FAST as possible you could do this:

Dive #1 - Multilevel 30m/19min followed by 10m/90min. You know you can do this as a multilevel profile because you would be an M after the first part and you needed to be a T to do the second part.....

And Dive #2 16m/42min

In that case you would be W coming out of the first dive which requires a 60min SI but it just happens to be exacly what you need to make dive #2.

So your total runtime would be

Dive#1 - 90+19+3+60
Dive#2 - 42+3

The total run time is now 214 instead of 237.

It does introduce a reverse profile of less than 40ft, which according to recent research doens't carry a significantly larger DCS risk and you create a little gas management issue during the first dive. In my case I would have to do the first dive with a twin-15 (double 104). In reality even though it fits in the tables I wouldn't recommend it.

R..

OK, now your just confusing the poor student. :06:

Question: Why are you working from a picture? Did you not get a Recreational Dive Planner along with your manual in the OW package?

The RDP has been updated over the years, however the photo in the manual is just for illustration purposes and may be decades old. The photo of the RDP in a manual can in no way be used as a substitute for the RDP.

You should be asking "where is my RDP" from the dive shop or instructor. If this is a PADI course, the RDP and manual must accompany the course, as well as the little yellow log book, or the full binder version of the log book.

 

[in_cavediver]

..... unless you mean the thing about surface intervals in the W to Z range...... In that case the 2nd surface interval would need to be 1 hour instead of 12 min. If you were following this rule you'd end up with answer of 240 min..... The version of the RDP I have doesn't stipulate this but I think the newer versions do..... I'll edit my original answer to reflect this.....

R..

Actually if you really want the fastest time, you would lengthen the first surface interval so that your 2nd dive ending pressure group was a V not an X, hence the lack of the 60 mintue min SI. If you do this, I came out with the min runtime of 204 mins. (give or take since I used an English RDP and converted).

Now, saying that, only a fool would attempt to dive this way.

Mike

 

[Diver0001]

Actually if you really want the fastest time, you would lengthen the first surface interval so that your 2nd dive ending pressure group was a V not an X, hence the lack of the 60 mintue min SI. If you do this, I came out with the min runtime of 204 mins. (give or take since I used an English RDP and converted).

Now, saying that, only a fool would attempt to dive this way.

Mike

ooohh that's also clever!

R..