OVM Dive Planner
OVM Dive Planner is a browser-based dive-planning simulator for open-circuit and CCR dives. It calculates decompression schedules using a Bühlmann ZH-L16C model with gradient factors and includes gas planning tools such as deco gas handling, repetitive-dive carry-over, and a gas mixer.
This browser version supports Bühlmann ZH-L16C with gradient factors, OC, CCR, bailout, multilevel profiles, repetitive dives and ideal-gas mixing. It does not offer VPM.
The main flow is dive settings, gases, profile, then results. Expand advanced settings for rates and surface conditions. Choose a predefined iOS gas for the bottom gas, CCR diluent and deco/bailout gases. Compositions are fixed; expand a deco gas to edit its switch depth. Each deco gas can be selected once. Expand “Edit exact depths and times” below the chart for numerical waypoint editing.
With “Include travel in level time” enabled, each level duration includes transit from the preceding depth. Otherwise it specifies hold time. A level cannot be shorter than its included transit.
The first decompression anchor may have zero hold time. The table lists positive holds, simulated in whole minutes. Cumulative runtime columns round up to whole minutes; the chart follows the exact simulated timeline.
Gas use is estimated from SAC and ambient pressure. CNS and OTU are modelled oxygen-exposure totals. END is explicitly nitrogen-only. These outputs are estimates, not measurements.
Editing a calculation input clears the current results and chart overlays. Changing units preserves the physical inputs and updates their display.
CCR uses low/high setpoints on the entered profile and a separate decompression setpoint on ascent. Bailout starts from the end-of-profile tissue state. Diluent is the initial OC bailout gas until an eligible richer bailout gas becomes available.
Bailout runtime starts at bailout. Its gas consumption, average depth, CNS and OTU describe the ascent only, excluding the preceding CCR exposure.
Enable repetitive diving, enter a surface interval and edit Dive 2. OC Dive 2 can use its own bottom gas; CCR Dive 2 can use its own diluent. An empty Dive 2 deco/bailout list inherits Dive 1 gases.
Tissues are carried through an air-breathing surface interval. CNS uses a 90-minute recovery half-life approximation, and OTU is carried forward. Editing either dive clears the displayed calculations.
Invalid numbers and gas compositions must be corrected before calculation. Entered multilevel ascents that cross the model ceiling are rejected. If a profile ends shallower than the selected last stop while still requiring decompression, revise that profile endpoint. Calculation limits and non-finite results produce an error rather than an incomplete schedule.
Tank Fill calculates passive pressure equalization between donor and target volumes. Top-Off Blend calculates the final composition after adding a specified gas. Trimix Mix calculates oxygen, helium and air additions accounting for oxygen supplied by air.
The calculators assume ideal gases, equal temperature and a consistent pressure reference. Impossible additions are rejected. Editing an input hides the previous result. Real-gas calculations are not included.
Open the website online once to install its offline assets. The planner, mixer and manual are cached. Offline installation requires HTTPS or localhost; it does not work when opening files directly.
When an update is ready, use the update button to reload the planner. Reloading clears unsaved inputs. Calculations remain local to your browser.
This application is for educational and simulation purposes only and must not be used for actual dive planning or execution. It is not a substitute for certified dive computers, professional training or sound diving judgment. The model may contain errors and does not account for individual physiology or actual dive conditions.