diff --git a/Documentation/images/pscr_b1.jpg b/Documentation/images/pscr_b1.jpg new file mode 100644 index 000000000..c7251b480 Binary files /dev/null and b/Documentation/images/pscr_b1.jpg differ diff --git a/Documentation/images/pscr_b2.jpg b/Documentation/images/pscr_b2.jpg new file mode 100644 index 000000000..0058af0c8 Binary files /dev/null and b/Documentation/images/pscr_b2.jpg differ diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 42747014c..9abe2b544 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -19,7 +19,7 @@ image::images/Subsurface4Banner.jpg["Banner",align="center"] Linus Torvalds, Miika Turkia, Amit Chaudhuri, Jan Schubert, Salvador Cuñat, Pedro Neves, Stefan Fuchs -[blue]#_Version 4.7, October 2017_# +[blue]#_Version 4.7, May 2018_# Welcome as a user of _Subsurface_, an advanced dive logging program with extensive infrastructure to describe, organize, interpret and print scuba @@ -3993,6 +3993,40 @@ in the loop due to the oxygen drop across the mouthpiece of the pSCR equipment. image::images/Planner_pSCR.jpg["FIGURE: Planning a pSCR dive: setup",align="center"] +==== Planning for pSCR bailout + +[icon="images/pscr_b1.jpg"] +[NOTE] +Open circuit diving is often part of a pSCR dive because, at shallow depths, the pO~2~ in the loop is often +too low for breathing and the shallow parts of a pSCR dive are often done on OC. The change +from rebreather mode to OC or _vice versa_ is indicated using bailout events. The image on the +left shows a pSCR dive plan (using three cylinders) where the shallow parts of the dive are performed using EAN50 in +order to have a sufficient pO~2~. The bottom part of the dive is perfomed with EAN31 (Cyl. 2 in the +*Available gases* table, also indicated in the *Dive planner points* table). The third cylinder, +also EAN31, is a bailout cylinder which is, initially, not used. +In this case the plan is for a cave dive with a bottom time of 20 minutes +and the turning point in the bottom part of the dive is at 16 minutes (i.e. ten minutes +into the bottom part of the dive). The orange pO~2~ graph indicates the equivalent OC pO~2~ during +the dive and the green pO~2~ indicates the estimated pO~2~ in the loop, the +whole dive being performed in rebreather mode. We wish to plan +for a worst-case scenario with bailout at the turning point (i.e. the furthest point into +the cave). In the *Dive planner points* table, change the *Dive mode* of the last two segments +to *OC* (indicated in the left-hand image, labled *A*, below). In this case the existing EAN31 +cylinder (Cyl.2 in the *Dive planner points* table is used for bailout (i.e. the bailout +cylinder [Cyl. 3] has not been used yet). Note that the pO~2~ graph now indicates the appropriate +pO~2~ values, since the gas breathed now has the pO~2~ of an OC configuration. In order to switch +to the bailout cylinder (Cyl. 3), indicate this by selecting the appropriate cylinder in the *Dive planner points* table as +indicated in the image on the right, below (labeled *B*). The icon on the depth profile +now shows an overlapping bailout event with cylinder change. As in the graph on the left, the appropriate +pO~2~ values are shown in the pO~2~ graphs. The volumes of gas required can be obtained at the bottom of the +*Dive plan details* panel. + +image::images/pscr_b2.jpg["FIGURE: Planning a pSCR dive: setup",align="center"] + +In the case of a pSCR dive plan for open water, the worst-case scenario is probably bailout at the end of the deepest part of the dive. +Create a 1-minute segment at the end of the deepest part of the dive plan. This +last segment (represented by the bottom row of the *Dive planner points* table) is then manipulated using the *Dive mode* and *Used gas* +columns, as in the cave example, above. See the example of bailout for a CCR dive, below, that uses this approach. === Planning CCR dives @@ -4044,6 +4078,7 @@ In order to plan for bailout to an external bailout cylinder, change the _Used appropriate cylinder, as in the example on the left. Note that the cylinder change as well as the bailout are indicated with overlapping icons. +The volumes of gases required for bailout can be found at the bottom of the *Dive plan details* panel. [[S_Replan]] === Modifying an existing dive plan