USN table questions. Get one to answer Flashcards
A diver has a job to do at 60 fsw table. He left botton after 64 minutes. In which repetitive group is he placed on?
a. K
b. L
c. N
d. O
b
A diver has been in the water for 56 minutes at 63fsw. In what table would you schedule his decompression?
a. 60/70
b. 70/70
c. 70/60
d. 60/80
c
A diver has been in the water for 56 minutes at 63fsw. During the dive the weather and sea conditions turns to worst. In which repetitive group he will be in? What decompression the supervisor should use?
a. Group K - No stops required
b. Group M - No stops required
c. Group M - 14 minutes at 20ft
d. Group M - 0.5 of O2 period in the chamber
d
A diver had an inspection work at 72fsw. He is scheduled to be on 80/60 table.
After 50 minutes you have taken a pneumo reading and a he is actually 9 feet deeper than you expected. What is your course of action?
a. Re-read the pneumo and put him on 90/50 table
b. Decompress the diver as planned on 80/60 table
c. Re-read the pneumo and put him 90/60 table and give him one full period in the chamber
d. Decompress the diver on the 90/60 table and give him half period in the chamber.
c
After a dive at 76 fsw for 46 minutes, the diver had a surface interval of 4 hours and is scheduled for a repetitive dive at 35 fsw. In what group will he be at the end of his decompression and what is the maximum time he can spend at 35 fsw?
a. Group M - 101 minutes
b. Group I - 101 minutes x
c. Group I - 105 minutes
d. Group M - 116 minutes
b
In your Company’s manual it states that the limit of a water decompression stop is 30 minutes. Your diver has a dive to do at 77 fsw and he spends a total of 55 minutes. What choices of decompression and table schedule do you have?
a. 30 minutes water stop or 1 full period of O2 in the chamber - table 80/60
b. 24 minutes water stop or 0.5 period of O2 in the chamber - table 80/55
c. No water stop allowed, only 0.5 period of O2 in the chamber - table 80/60
d. No water stop allowed, only 1 full period of O2 in the chamber - table 80/60
a
After 3 hours and 28 minutes rest, a diver is set for a repetitive dive at 45 fsw.
What is the maximum time he can work at this depth and what group he will be at the beginning of his surface decompression interval? His first dive was logged on the 110/40 table.
a. 93 minutes - Group K
b. 93 minutes - Group M
c. 93 minutes - Group N
d. 96 minutes - Group K
c
Divers make a dive to 115 fsw. Stage depth is 113 fsw. Bottom time
is 55 minutes. According to the 120 fsw / 55 min decompression schedule, the first decompression stop is 30 fsw. During ascent, the divers were delayed at
100 fsw for 3 minutes 27 seconds and it actually took 6 min 13 seconds to reach
the 30-foot decompression stop. Determine the new decompression schedule.
a. 120/55
b. 120/60
c. 120/70
d. 130/55
PS: Delay greater than 1 minute, deeper than 50 fsw. Round up the delay
time to the next whole minute and add it to the bottom time. Recompute the
decompression schedule. If no change in schedule is required, continue on
the planned decompression. If a change in schedule is required and the new
schedule calls for a decompression stop deeper than the diver’s current depth,
perform any missed deeper stops at the diver’s current depth. Do not go deeper.
b
Divers made a dive to 113 fsw. Bottom time was 60 minutes. According
to the Air Decompression Table, the first decompression stop is at 30 fsw. During
ascent, the divers were delayed at 40 fsw and it actually took 6 minutes 20
seconds to reach the 30-fsw stop. Determine the new decompression schedule.
a. Keep 120/60 table and add the delay time to the first decompression stop
b. Reschedule the dive to 120/70 table
c. Reschedule the dive to 130/60 table
d. Bring to surface and put the diver in the chamber on 100% O2 at 18 meters
PS: Delay greater than 1 minute, shallower than 50 fsw. If a delay in ascent
greater than 1 minute occurs shallower than 50 fsw, round the delay time up to
the next whole minute and add the delay time to the diver’s first decompression
stop.
a
A diver is trapped on the bottom at a depth of 155 fsw. By the time he
is freed, the bottom time is 100 min. The longest schedule in the 160 fsw table is
80 min. What do you do?
a. Read down to the 170 fsw table. The 120 min schedule is longer than the diver’s bottom time. Decompress the diver on the 170 fsw / 120 minute schedule.
b. Decompress the diver on a 160 fsw / 80 minutes schedule.
c. Bring him to the surface, give 100% O2 and watch for DCI.
d. Call for help
a
A repetitive dive is planned to 98 fsw for an estimated bottom time of 15 minutes. The previous dive was to a depth of 101 fsw and had a bottom time of 48 minutes.
Decompression was conducted using the in-water air/oxygen option. The diver’s
surface interval is 6 hours 26 minutes. Answer following questions.
a. What group will he be at the beginning of his Surface interval?
b. What group will he be at the end of his Surface interval?
c. What is his Residual Nitrogen Time (RNT) at 98ft?
d. What is his equivalent single dive time?
e. What is the proper decompression schedule for the repetitive dive?
f. If he is doing a in water decompression, at what depth is the first stop and how long would the diver be in there?
a. Group Z
b. Group I
c. 30 minutes
d. 30 minutes of RNT + 15 minutes estimated bottom time = 45 minutes
e. 100/45 table schedule
f. Would be 36 minutes at 20ft stop.
Divers are decompressing on a SurDO2 schedule that requires 1.5 oxygen breathing periods. It took 6 minutes and 20 seconds to travel from 40fsw to the surface, undress the diver, and recompress to 50 fsw in the chamber. What do you do?
a. Decompress the divers as normal schedule
b. Increase 15 minutes as penalty for at 50fsw. Give him in total 2 periods
c. Put him on table 5 as a treatment for his delay
d. Put him on table 6 as a treatment for his delay
PS: Surface Interval Greater than 5 Minutes. If the surface interval is more than 5 minutes but less than or equal to 7 minutes, increase the time on oxygen at 50 fsw from 15 to 30 minutes, i.e. add one-half oxygen period to the 50 fsw chamber stop. Ascend to 40 fsw during the subsequent air break. The 15-min penalty is considered a part of the normal surface decompression procedure, not an emergency procedure.
b
A Diver is schedule 1 full period of SurDO2 after been 50 minutes bottom time at 100fsw. On the way up at 30fsw the air winch fails, and he takes 7 minutes and 33 seconds to get on oxygen at 50ft in the chamber. What your course of action?
a. Decompress the diver as planned.
b. Increase 0.5 period at 50ft as penalty and decompress him as normal.
c. Treat him in Table 5
d. Treat him in Table 6
PS: If the surface interval is greater than 7 minutes, continue compression to a depth of 60 fsw. Treat the divers on Treatment Table 5 if the original schedule required
2 or fewer oxygen periods in the chamber. Treat the divers on Treatment Table
6 if the original schedule required 2.5 or more oxygen periods in the chamber.
c
After a dive 125fsw for 26 minutes bottom time, the diver is schedule to do 1 full period of a SurdO2. As he enters the chamber he experience problems to equilize ears and ask the pressurization process to be stopped at 20ft. What is your course of action in this situation?
a. Surface the diver and give him 100% O2.
b. Force pressurization until chamber reach 50ft depth.
c. Double the number of chamber oxygen periods indicated in the table and take these periods at the deepest depth the diver is able to attain. Interrupting O2 breathing every 60 minutes with a 15-min air break.
d. Put the diver back in the water and decompress as scheduled.
c
