ANSWERS to (RDP)Practice Questions
JB OW RDP Answers
1) 1 What pressure group would a diver be in after a 15 minute dive to a depth of 70 feet?
answer a) E
Side 1 RDP, find 70 foot mark, go down until you find the exact time or next greater time if exact time not listed.
15 minutes is on it and then go across and you’ll see pressure group E
2) What pressure group would a diver be in after a dive to 45 feet for 50 minutes?
answer c) P
Side 1 RDP Need to go to 50 feet cause there is no 45 foot depth mark. Then go down until find 50 minutes.
Go across and you’ll see you’re in pressure group P
3) A diver does a dive to 80 feet for 20 minutes. What is his pressure group after a 22 minutes surface interval?
answer b) H
Side 1,Go to 80’ and then down to 20 minutes. Go across you see pressure group K. Then go across until you find where 22 minutes falls in on table 2 of side 1. You’ll find a box with 0:17 and 0:22. Follow down to pressure group on bottom and it’s pressure group H
4) A diver does a series of dives and is in Pressure group L. What will his pressure group be after a surface interval of 40 minutes?
answer a) F
Start on pressure group L: on left side and go across until find where 40 minutes falls. You find 0:35 and 0:42. Follow down to pressure group F
5) What is the ending pressure group for the following 2 dives?
First you dive to 48 feet for 25 minutes. Surface interval of 30 minutes then dive to 40 feet for 1 hour.
answer d) S
Figure out the RAT!
Go to 50’ then down to 26 min you’re in pressure group G.After Surface Interval, you’re in pressure group D .
Go to Side 2. Since 2nd dive is to 40’ Go to 40' and find where it intersects with pressure group D. To find the RNT (Residual Nitrogen Time) which is in the white box. Which is 25 min. Add the RNT of 25 to the ABT (Actual Bottom Time) of the dive (in this case 60 min(1 hour)) for a TBT (Total Bottom Time) OF 85 MIN.
Go back to Side 1 and 40’depth for time of 85 minutes(TBT)TOTAL Bottom Time pressure group is S.
6) A diver does a dive to 55 feet for 46 minutes. Surface interval of 1 hour followed by a dive to 50 feet for 45 minutes.
What is her ending pressure group?
answer c ) V
Figure out the RAT!
Side 1, Go to 60 foot depth because there's no 55'.
Go down to find 46 minutes. There is no 46 so you must go to 47.Go across table from 47 and you see you are in (PG) Pressure Group S. Go across from S and find your surface interval time of 1 hour. You find a box with :57 & 1:03. (57 minutes & 1 hour 3 minutes)
1 hour falls inbetween so that's the column you use.
Go Down the column and it shows what (PG) pressure group you're in after the surface interval. In this case it is G .
Now go to side 2 to figure out the RNT, (Residual time).
Find where the depth of dive 2 (50 feet) and the beginning pressure group of G intersect.
Residual is the white box at the intersect of 50 & G and is 26 minutes.
Figure out the RAT!. R plus A = T. (Residual plus actual = TOTAL. )
Add the Residual of 26 to the Actual bottom time of 45 minutes and you get a TOTAL bottom time of 71 minutes.
Go back to side 1. Find depth of second dive (50 feet) and go down to the TOTAL bottom time of 71 minutes and you find you are in pressure group (PG) V
7) What is the ending pressure group after the following 3 dives?
Dive to 80 for 22 minutes followed by a 45 minute surface interval
Dive to 60 feet for 30 minutes followed by a 50 minute surface interval
Dive to 50 feet for 25 minutes.
answer a) Q
8) What would your ending pressure group be after the following scenario:
Dive to 87 feet for 20 minutes Surface interval of 1 hour and 6 minutes
Dive to 60 feet for 40 minutes. Surface interval of 1 hour
Dive to 42 feet for 35 minutes
answer c) T
9) What is the maximum allowable bottom time for a dive to 72 feet?
answer a) 30 min
(maximum allowable bottom time for a single dive is (NDL) No Decompression Limit)
10) What is the maximum allowable bottom time for a depth of 100 feet ?
answer d) 20 min
11) You do a dive to 62 feet for 25 minutes. After a surface interval of 40 minutes you want to dive to 46 feet.
What is the maximum allowable bottom time for the second dive?
answer c) 56 min
(Max bottom time for a repetitive dive is the (ANDL) Adjusted No Deco Limit)
Calculate all info given.
2nd dive you start in pressure group F. Dive is to 46’. Side 2 where 50’ and F intersect the ANDL (blue box) is 56 min.
12) On vacation in the Bahamas you do 2 dives. Dive 1 is to 71 feet for 20 minutes. Dive 2 is to 60 feet. If you have a surface interval of 20 minutes what is your maximum allowable bottom time for dive 2?.
answer c) 32
(Adjusted NDL for a diver in pressure group h going to 60 feet is 32 min)
13) While on vacation you do 2 boat dives in the morning.
1st dive to a wreck in 90 feet for 20 minutes. Then a 38 minute surface interval
2nd dive on a coral reef to 51 feet for 30 minutes.After lunch you and your buddy decide to do a shore dive behind the hotel. The reef there is 47 feet.
You check your computer and it shows a surface interval of 2 hours and 6 minutes.
What is the maximum allowable bottom time for the third dive?
answer b) 67 minutes
Find the ANDL of the last dive! Find where 50 ‘ and B intersect on side 2 . The blue box is the ANDL
14) Minimum surface Interval
What is the minimum surface interval required for a dive to 50 feet for 50 minutes and another dive to 50 feet for 40 minutes?
b) 17 min
-Calculate dive 1,pressure group (P). Go to Side 2 and go to depth of dive2,(50’) Go across 50’ line until find dive time or next greater time of dive 2 (40 min) in the blue boxes. Go up and find pg (L). Go to side 1 and find where the 2 pressure groups intersect. Box :17 :21. Talk lowest time because it’s the MINIMUM time needed.
15) What is the minimum surface interval between these 2 dives.
Dive to 80 feet for 25 minutes and a dive then to 51 feet for 42 minutes?
answer b) 1:31 (1 hr 31 min)
16) A divers non-diving friend is getting married on a summer Saturday. The ceremony ends at 11:OO AM. The reception begins at 4 PM so the diver figures he can squeeze in a quick dive or two. If her first dive is to a depth of 70 feet for 30 minutes, what is the minimum surface interval for a second dive to 60 feet for 35 minutes?
answer C) 48 min
17) A diver makes a dive to 70 feet for 33 minutes.He waits for a surface interval of 32 minutes before diving to the same depth (70 feet).Forgetting to monitor his bottom time he finally checks his watch and discovers he’s been diving for 24 minutes. According to the RDP, what should the diver do in this situation?
d) Ascend to 15 feet and stay there for no less than 15 minutes (air supply permitting) and upon surfacing remain out of the water for at least 24 hours.
( Look at Emergency Decompression Procedures on back of the RDP)
They are asking you to figure out how long the diver went past his ANDL (Adjusted No Deco Limit) for the second dive.Remember, an Adujusted No Deco limit is the maximum time you can stay at a specific depth with a specific beginning pressure group on a repetitive dive.
Once you figure out the ANDL you need to remember, or look at the Emergency Decompression Rules and follow them.
So you do dive # 1 just as you always do. Then do dive # 2 but instead of figuring out the RAT for dive # 2, look up the ANDL (blue box that corresponds with the beginning pressure group of dive #2 and the depth of dive #2.
In this case depth is 70 feet and (pg) J.
The ANDL is 18 minutes. Since he stayed at 70 feet for 26 minutes he went past his ANDL by 6 minutes(26 - 18 = 6).
18) A group of advanced divers plan 2 dives on Long Island shipwrecks.
One dive is to the artificial reef near Shinnecock. They plan to dive to 70 feet for 30 minutes.
The other dive is to the U.S.S. San Diego and plan a 110 foot dive for 10 minutes.
Surface interval will be 1 hour and 45 minutes.
Which dive should they plan to do first?
answer b) The 110 foot dive
(Do your Deepest dive first.)
19) You dive in water near freezing temperatures. Your dive plan is to dive to 72 feet for 20 minutes.
What profile would you use with the RDP to plan this dive?
answer b) 90 feet for 20 minutes
(In cold water plan your dive as if it was 10 feet deeper. Therefore 82’ for 20 minutes, you’d go to 90 ‘ on the RDP
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