Robert,
Your last patch for a button that enables bailout planning greatly
improves the user experience. I have one question. Frequently in CCR
diving the last part of deco is performed using bailout. In semiclosed
rereathers, a significant part of the ascent is often performed in OC
mode (=bailout) because remaining on the loop extends the deco time
significantly and can also affect PO2 unfavourably. In eCCR dives, the
oxygen part of the deco is often done off the loop because the 2 litre
oxygen cylinder does not contain enough oxygen for the deco (this last
point is a technicality from the planning point of view, not a
substantive issue).
When planning a dive and there is planned bailout, it is currently
difficult do this sort of planning. For instance, let us take a normoxic
trimix SCR dive for which the last two stages of decompression is using
EAN50 and oxygen. To plan for deco off the loop (=bailout) for EAN50 and
oxygen, the only way that I can see is to do the planning without
bailout, record all the depths and time durations of ascent that comes
from this plan, then enter, in the dive planner points table, all the
additional segments during ascent up to the point where the bailout to
EAN50 is performed. The planner will then compute the remaining bailout
part of the dive plan.
In multideco, this is not a problem because there is a separate list of
OC cylinders that one can select, and when a cylinder is marked as OC,
then the appropriate bailout (=off-loop) calculations are done.
Within Subsurface, I propose that, in the available gases table, an
additional "Use" is created: bailout. Technically the "Use" of OC-gas is
not valid in CCR dives, but that is another different issue). The
categories would then be: OC-gas, unused and bailout. When the planner
calculates an ascent profile and a cylinder is marked as "bailout" then
the calculations are modified appropriately. I think the change to the
UI to do this is trivial: the real work comes in including this in the
deco algorithm.
I hope my argument is understandable??
Kind regards,
willem
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