Run Times...explain please?

[Paddy Diver]

Think I have an idea of what there are so here goes..
"A specific time spent at a certain depth and in which to arrive at another pre-determined depth"
Is this right or am I way off the mark? Any info would be greatly welcomed.


Thanks,
Ian

[Admin Edit: 'Rintime' typo in title duly edited]

[jptaylor9]

Do you mean runtimes?

Runtimes are times you leave specified depths allowing for both stop time & ascent time. Given a schedule of depths/runtimes you can execute dive using a dive time. You just need to know depth & elapsed time on dive.

E.g.

The Drogon Dive Planner [v2:
================================

Dive profile for default:
Step Depth SegT RunT
================================
1 0.0-> 51.0 3:24 3:24
2 51.0-> 51.0 21:36 25:00

Deepest effective stop: 36m
Buhlmann + Gradient Factor decom
Step Depth SegT RunT
================================
3 51.0-> 30.0 3:00 28:00
4 30.0-> 27.0 1:00 29:00
5 27.0-> 24.0 1:00 30:00
6 24.0-> 21.0 1:00 31:00
7 21.0-> 18.0 2:00 33:00
8 18.0-> 15.0 3:00 36:00
9 15.0-> 12.0 5:00 41:00
10 12.0-> 9.0 7:00 48:00
11 9.0-> 6.0 51:00 99:00
12 6.0-> 0.0 0:36 99:36
================================
Dive time: 0:25:00
Ascent & Deco time: 1:14:36
========
Total run time: 1:39:36

[And]

Hi

AFAIUI a 'runtime' is a specific time of the dive at which you are supposed to be at a given depth.

Your deco schedule is based upon this, and you may have a different set of tables for different scenarios, 5 minutes longer, 5 mtrs deeper etc.

The main thing is that at minute 43 (for example) you switch to your first deco gas.

Don't know whether thats any clearer or not

Andy

[Mal Bridgeman]

Originally Posted by And

The main thing is that at minute 43 (for example) you switch to your first deco gas.

Hi Andy


I am being a little pedantic ....One should be on schedule with both depth and time so your statement is true but importance of depth in the gas switch should be stressed IMHO

Mal

[nigelH]

Run times are just an easy way to record the planned profile.

The slate on your wrist gives you the time at which things are supposed to happen and the watch or depth/timer gives you the time. You just have to make sure things happen on schedule.

Knowing you have to do 2 minutes at such a depth and 8 minutes at another and 27 minutes at a third commits you to a list of mental arithmatic and remembering things. Complicated things don't work in your brain under water. Knowing I leave this stop when the time reaches 43 is much easier.

[vid]

Originally Posted by nigelH

Complicated things don't work in your brain under water.

absolutely agree - avoid doing any calcualtions underwater

Originally Posted by nigelH

Knowing I leave this stop when the time reaches 43 is much easier.

the down side to this, is that you have to be absolutely rigid in sticking to the dive plan (or alternatively, have lots of different plans of varying lengths written on your slate, so if you overstay at the bottom you have a contingency)

vid

[Gareth J]

Vid

As a general rule, if you are using run times you are not doing recreational diving. But the more adventurous diving, this requires discipline.

People using runtime general are very disciplined, They have specified MOD's, optimum mixes & specified times & depth. They do not change the dive on the fly.
If people are not happy with this approach, then doing the type of diving that requires runtime's, is probably not for them.

I personal carry three plans:-
A short plan - so I can exit immediately if I wish to abort.
A standard plan - the expected dive
A maximum plan - this is the maximum safe plan with optimal gas calcs etc - used if the dive is exceptionally good - or it goes to rat shit & I over run due to problems.
I also carry a duplicate sheet of the above & failed deco gas, failed travel gas failed deco & travel gas plans.

The main point of the runtime is that it significantly reduces the risk of a mistake when carrying out complicated dives with extensive decompression & multiple gases.
It also means that the dive team know where everyone should be at any given time throughout the dive.
When team diving using deco stations it means that you can optimise the order to ensure all divers are on station at the right time. This is very reassuring when you have a team in the water, on a high risk dive.

One other nice bonus is that the skipper has your tea ready as you exit the water!

[Mark Chase]

If like me you use computers for deco....

To me bottom time is guess what the time spent at planned depth, deco is the time spent on decompresion and run time is the total in water dive time.

ATB

Mark Chase

[Paddy Diver]

Ok cool that clears up that question.
No I dont do this type of diving, well not yet anyway but I just wanted to know anyway for when I reading stuff thats way over me head




Thanks
Ian