Plan Dive -- thoughts

[Joakim Bygdell]

> On 27 Feb 2015, at 21:23, Steve Butler <kg7je at comcast.net> wrote:
> 
> Now, as an OC rec diver (soon to have access to the 100-130 depths) I would not want to enter the ascent segments separate from spending time at a level on the way up in order to indicate to ascend at best rate.  Take this scenario:
> 
> Drop to 130 and hang there for 6 minutes (28% O2).
> Rise at 30'/m to 70 and hang there for 8 minutes on the ledge.
> Ascend at 30'/m to 40 (no wait as it is a transition to an upslope.
> Spend 5 minutes swimming the upslope to 15.
> Spend the standard 3 minute stop at 15.

As this is a multilevel dive you have to do some calculation on your own, i.e transition times between the levels.

Final Depth	Duration	Runtime
130			2		2			descend
130			6		8			level
70			2		10			ascend
70			6		16			level
15			5		21			swim upslope
15			3		24			stop

When you do that the ascent rates that you can set tin the lower left cornet of the planner will not be used.
The descent rate will be used only if you check “Drop to first depth”. And in this case it will replace the first two lines with this.

130			8		8

Containing both the descent time and the time spent at 130’.

> 
> Oh, and option to pick between 15 or 20'.  I noticed only 20' was set as the last stop.

That is because the planner used 10’ increments in its internal calculations.
And the planner will only calculate what reamins on the ascent after your last waypoint.


Compare how the planner works on your example vs. a blue water ascent profile.
The only thing entered into the planner is this line with “Drop to first depth” checked.

Final Depth	Duration	Runtime
130			13		13

In this case the planner will tell you that the calculated ascent from 130ft, using the defined ascent rates, will take 7minutes.



Multilevel dives you have to define all waypoints for all the levels, until the start of the ascent that contains your safety stop.
In the first example if the upslope didn’t exist your last waypoint would be @ 70’ and the planner would calculate the ascent time to the surface.
Since you don’t have any deco obligation it will tell you that you can ascend to the surface using the defined ascent rates over a time of 4min.


> 
> -- 
> Stephen M Butler, PMP, PSM
> kg7je at comcast.net
> kg7je at arrl.net
> 
> _______________________________________________
> subsurface mailing list
> subsurface at subsurface-divelog.org
> http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface

/Jocke