diff --git a/Documentation/images/rec_diveplan.jpg b/Documentation/images/rec_diveplan.jpg new file mode 100644 index 000000000..c09a9c2b1 Binary files /dev/null and b/Documentation/images/rec_diveplan.jpg differ diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 771960d97..6ea29b7e8 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -2767,6 +2767,7 @@ This panel allows two type of selections: ** _Show unused cylinders in Equipment Tab_: This checkbox allows display of information about unused cylinders when viewing the *Equipment Tab*. Conversely, if this box is not checked, and any cylinders entered using the *Equipment Tab* are not used (e.g. there was no gas switch to such a cylinder), then these cylinders are omitted from that list. +[[GradientFactors_Ref]] ** _Show average depth_: Activating this checkbox causes _Subsurface_ to draw a grey line across the dive profile, indicating the mean depth of the dive up to a particular point in time during that dive. Normally this is a u-shaped line indicating the deepest average depth just before the @@ -2927,7 +2928,70 @@ image::images/PlannerWindow1_f20.jpg["FIGURE: Dive planner startup window",align - The dialogue indicating _Dive Planner Points_ is usually not used at this stage of the dive planning. -*The planning is performed in three stages* +==== Recreational dives + +The _Subsurface_ dive planner allows a sophisticated way of planning recreational dives, i.e. dives +that remain within no-decompression limits. +The dive planner automatically takes +into account the nitrogen load incurred in previous dives. But conventional dive tables are also used in a +way that can take into account previous dives. Why use a dive planner for recreational dives? Using +recreational dive tables, the maximum depth of a dive is taken into acount. However, few dives are +undertaken at a constant depth corresponding to the maximum depth (i.e. a "square" dive profile). This means that dive tables +overestimate the nitrogen load incurred during previous dives. The _Subsurface_ +dive planner calculates nitrogen load according to the real dive profiles of all uploaded previous dives, +in a similar way as dive computers calculate nitrogen load during a dive. This mean that the diver gets 'credit' +in terms of nitrogen loading for not remaining at maximum depth during previous dives, enabling planning a +longer subsequent dive. For the planner to work it is therefore crucial to upload all previous dives +onto _Subsurface_ before performing dive planning. + +To plan a dive, the appropriate settings need to be +defined. + +- Ensure that the date and time is set to that of the intended dive. This allows calculation of +the nitrogen load incurred during previous dives. + +- Immediately under the heading _Planning_ are two checkboxes _Recreational_ and _Safety Stop_. For +planning recreational dives, check these two checkboxes. + +- Then define the cylinder size, +the gas mixture (air or % oxygen) and the starting cylinder pressure in the top left-hand +section of the planner under _Available gases_. + +- The planner calculates whether the specified cylinder contains enough air/gas to complete +the planned dive. In order for this to be realistic, under _Gas options_, specify an appropriate +surface air consumption (SAC) rate for _Bottom SAC_. Suitable values are between 15 l/min and 30 l/min, +with novice divers or difficult dives requiring SAC rates closer to 30l/min. + +- Define the amount of gas in the cylinder at the end of the bottom section of the dive just before ascent. A +value of 50 bar is often used. + +- Define the depth of the dive by dragging the waypoints (white dots) on the dive profile or +(even better) defining the appropriate depth using the table under _Dive planner points_. If +this is a multilevel dive, set the appropriate dive depths to represent the dive plan by adding +waypoints to the dive profile or by adding appropriate dive planner points to the _Dive Planner Points_ +table. + +- The ascent speed can be changed. The default ascent speeds are those considered safe for recreational +divers. + +The dive profile in the planner indicates the maximum dive time within no-deco limits using the +Bühlmann ZH-L16 algorithm and the gas and depth settings specified as described above. The _Subsurface_ planner +allows rapid assessment of dive duration as a function of dive depth, given the nitrogen load incurred during previous dives. The +dive plan includes estimates of the amount of air/gas used, depending on the cylinder settings specified +under _Available gases_. If the initial cylinder pressure is set to 0, the dive duration shown is the +true no-deco limit (NDL) without taking into account gas used during the dive. If the surface above the dive profile is RED +it means that recreational dive limits are exceeded and either the dive duration or the dive depth needs to be reduced. + +Below is an image of a dive plan for a recreational dive at 30 metres. Although the no-deco limit (NDL) is 23 +minutes, the duration of the dive is limited by the amount of air in the cylinder, reflected by the information in the +text box at the bottom right of the panel. + +image::images/rec_diveplan.jpg["FIGURE: A recreational dive plan: setup",align="center"] + +==== Non-recreational open circuit dives, including decompression + +Non-recreational dive planning involves exceeding the no-deco limits and/or using multiple breathing gases. +Such dives are planned in three stages: *a) Nitrogen management*: This is performed by specifying the rates for descent and ascent, as well as the gradient factors (GFLow and GFHigh) under the headings _Rates_ and _Planning_ @@ -2952,7 +3016,6 @@ often in the range of 4-9 m/min. The descent rate is also specified. If the opti is activated, then the descent phase of the planned dive will be at the maximal descent rate specified in the _Rates_ section of the dive setup. - *b) Oxygen management*: In the *Gas Options* part of the dive specification, the maximum partial pressure for oxygen needs to be specified for the bottom part of the dive (_bottom po2_) as well as for the decompression part of the dive (_deco po2_). @@ -3041,6 +3104,25 @@ level is indicated in the _Dive Plan Details_. This duration INCLUDES the transi time to get to that level. However, if the _Display transition in deco_ option is checked, the transitions are shown separately from the segment durations at a particular level. +=== Planning pSCR dives + +To plan a dive using a passive semi-closed rebreather (pSCR), select _pSCR_ rather than +_Open circuit_ in the dropdown list. +The parameters of the pSCR diver can be set by selecting _File -> Preferences -> Graph_ +from the main menu, where the gas consumption calculation takes into account the pSCR dump +ratio (default 10:1) as well as the metabolism rate. The calculation also takes the oxygen drop +accross the mouthpiece of the rebreather into account. If the +pO~2~ drops below what is considered a save value, a warning appears in the _Dive plan +details_. A typical pSCR configuration is with a single cylinder and one or more bail-out +cylinders. Therefore the setup of the _Available gases_ and the _Dive planner points_ tables +are very similar to that of a CCR dive plan, described above. However, no oxygen setpoints +are specified for pSCR dives. Below is a dive plan for a pSCR dive. The dive is comparable +to that of the CCR dive above, but note the longer ascent duration due to the lower oxygen +in the loop due to the oxygen drop across the mouthpiece of the pSCR equipment. + +image::images/Planner_pSCR1_f20.jpg["FIGURE: Planning a pSCR dive: setup",align="center"] + + === Planning CCR dives To plan a dive using a closed circuit rebreather, select the _CCR_ option in the dropdown @@ -3065,25 +3147,6 @@ image::images/Planner_CCR1_f20.jpg["FIGURE: Planning a CCR dive: setup",align="c Note that, in the _Dive plan details_, the gas consumption for a CCR segment is not calculated, so gas consumptions of 0 litres are the norm. -=== Planning pSCR dives - -To plan a dive using a passive semi-closed rebreather (pSCR), select _pSCR_ rather than -_Open circuit_ in the dropdown list. -The parameters of the pSCR diver can be set by selecting _File -> Preferences -> Graph_ -from the main menu, where the gas consumption calculation takes into account the pSCR dump -ratio (default 10:1) as well as the metabolism rate. The calculation also takes the oxygen drop -accross the mouthpiece of the rebreather into account. If the -pO~2~ drops below what is considered a save value, a warning appears in the _Dive plan -details_. A typical pSCR configuration is with a single cylinder and one or more bail-out -cylinders. Therefore the setup of the _Available gases_ and the _Dive planner points_ tables -are very similar to that of a CCR dive plan, described above. However, no oxygen setpoints -are specified for pSCR dives. Below is a dive plan for a pSCR dive. The dive is comparable -to that of the CCR dive above, but note the longer ascent duration due to the lower oxygen -in the loop due to the oxygen drop across the mouthpiece of the pSCR equipment. - -image::images/Planner_pSCR1_f20.jpg["FIGURE: Planning a pSCR dive: setup",align="center"] - - [[S_Replan]] === Modifying an existing dive plan