Adv Wreck Exam

[lermontov]

Thers a a Q in the advanced wreck paper that goes like this

Based on a dive time of 45 min on air what is the total ascent time? (Depth of dive is 45m)
A) 86min
B) 90 min
C) 88 min
D) 92 min

No sure if that is meant to read bottom time not dive time
i ran it through the V planner and i get a total dive time of 151 min so not sure two answer this

any help please?

 

[fsardone]

We do not know what deco methodology you employ. Using only air your deco will be in eccess of twice the dive time at 45 meters.

Not enough data to help you!

 

[lermontov]

sorry there is more info to the Q
"the dive plan calls for a normoxic air bottom mix and EAN 75 deco gasses using a standard air DECO profile"

 

[fsardone]

There is no standard!
Using vpm conservativism 2 and EAN 70 from 12 M (1.53 ppO2) you get 110 minutes run time for 45 minutes at 45 meters including descent at 20 meters minute.

Cheers

 

[Jax]

Normoxic? by whose standards? Would that be 21/33/34? I've heard normoxic only with trimix.

If so, I get

3 min down
16 min bottom time,
and 15 min ascent time.
Total 45.

Well, straight air gives me the same.

If 45 min = bottom time,

103-45 = 68 min ascent.

 

[Jax]

This is all with deep stops, starting at 80.

 

[Diver0001]

Thers a a Q in the advanced wreck paper that goes like this

Based on a dive time of 45 min on air what is the total ascent time? (Depth of dive is 45m)
A) 86min
B) 90 min
C) 88 min
D) 92 min

No sure if that is meant to read bottom time not dive time
i ran it through the V planner and i get a total dive time of 151 min so not sure two answer this

any help please?

If I'm right this ia a TDI question. TDI doesn't have its own tables but there will be a selection of tables you can choose from in the back of the book. If it's not in the back of the wreck book then it will certainly be in the back of your extended range book. Use those.

The formal definition of bottom time using most tables is the time from the start of the descent to the start of a continuous ascent (not multi-level). So I would expect the 45min in the question to be bottom time.

The question appears to be what the ascent time would be if you were to grind out that dive on air. If you look on the US Navy tables for that depth and time it shows a total ascent time using air of 91 minutes.

R..

 

[Jax]

Thanks for the clarification, @Diver0001 !

 

[Diver0001]

sorry there is more info to the Q
"the dive plan calls for a normoxic air bottom mix and EAN 75 deco gasses using a standard air DECO profile"

Oh, I see. so they're asking you to work out how long the dive would be in total if your bottom time were 45 minutes.

Vplanner says 109 minutes. You'll have to look in the back of the book to see if they give you a table to use.

R..

 

[Jax]

Oh, I see. so they're asking you to work out how long the dive would be in total if your bottom time were 45 minutes.

Vplanner says 109 minutes. You'll have to look in the back of the book to see if they give you a table to use.

R..

I think you were right in the first place - the 91 minute ascent time matches (d) 92 minutes.