MAKE IT YOUR DIVE

Plan a dive.

Define the intent. Explore every moment.

Technical mode calculates your specified profile. Objective mode searches the final bottom hold on a one-minute grid within explicit limits; model settings and gases stay fixed.

Model used for this plan

The 5-minute variant uses fastest-compartment designation 1b (nitrogen half-time 5 minutes, helium 1.88 minutes); the 4-minute variant uses 1a (nitrogen 4 minutes, helium 1.51 minutes). These are theoretical tissue half-times, not stop durations. Exact variant identifiers remain in engine exports. Select the active calculation model. Previously configured settings are restored independently for each model. VPM-B/E remains pending and cannot be calculated. Switching model invalidates the previous result.

Primary diving mode

Choose how this dive will be performed. OC shows breathing gases; CCR shows diluent, setpoints and loop supplies, with OC bailout separate.

Scenario name

A short name saved with the exact inputs. It does not select a preset or change calculations.

Profile levels
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Travel is added between levels using your declared profile travel rate. Hold time is time at that depth, not runtime since descent. The final hold is searched in objective mode.

Depth · m

Target depth at this level. The website accepts positive depths up to 150 m.

Hold · min

Time at this level, excluding travel. Objective mode changes only the last level's hold.

Breathing supply

Actual cylinder identity used for this profile level. Travel to the level uses this source too; include a travel-gas level where needed.

OC ascent: gas changes
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Actual gas, diluent or setpoint events, independent of which equipment is available. Choose the same cylinder again for a setpoint-only CCR change. Engine validates exact depths and order.

At depth · m

Exact depth of the ascent source change. Must be between the starting ascent depth and surface; deeper changes execute first.

Hold · s

Declared stationary hold immediately after this change. Included in exposure and gas use.

Source cylinder

Cylinder actually supplying this event. Select the current cylinder for a CCR setpoint-only change; it does not invent a new gas supply.

At depth · m

Exact depth of the ascent source change. Must be between the starting ascent depth and surface; deeper changes execute first.

Hold · s

Declared stationary hold immediately after this change. Included in exposure and gas use.

Source cylinder

Cylinder actually supplying this event. Select the current cylinder for a CCR setpoint-only change; it does not invent a new gas supply.

Equipment
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Use my cylinders checks whether the cylinders you entered provide enough gas for this dive and the selected contingency. Suggest cylinder sizes selects capacities for the gases you chose, using the available size list. You still choose gas mixtures, switch depths, starting pressures and reserves. It does not choose gases, add separate stages or design the gas plan.

Enter the cylinders you have. The calculation checks their gas quantities against your dive and selected contingency.

Back gas 18/45 · 24 L

Name

Display name. The immutable cylinder ID keeps physically distinct supplies separate.

O₂ · %

Oxygen fraction by volume. Nitrogen is the remainder after oxygen and helium. Composition alone does not establish suitability.

He · %

Helium fraction by volume. Oxygen plus helium must not exceed 100%.

Size · L

The cylinder size, not the amount of gas at its filling pressure. For a connected pair of two 12 L cylinders, enter 24 L. Separate cylinders are entered individually. Suggest sizes chooses from 3, 7, 11, 12, 15 L cylinders or connected 2 × 12 / 2 × 15 L pairs.

Start · bar gauge

Pressure above the site's ambient surface pressure. Converted to absolute pressure for the engine.

Reserve · bar gauge

Declared reserve pressure above ambient. Unmet reserve is a reported gas shortfall.

Volume convention

Ideal gas assumes Z=1. Declared compressibility uses your starting/reserve endpoint Z values; intermediate pressure is not inferred.

Deco 50 50/0 · 11 L

Name

Display name. The immutable cylinder ID keeps physically distinct supplies separate.

O₂ · %

Oxygen fraction by volume. Nitrogen is the remainder after oxygen and helium. Composition alone does not establish suitability.

He · %

Helium fraction by volume. Oxygen plus helium must not exceed 100%.

Size · L

Start · bar gauge

Pressure above the site's ambient surface pressure. Converted to absolute pressure for the engine.

Reserve · bar gauge

Declared reserve pressure above ambient. Unmet reserve is a reported gas shortfall.

Volume convention

Ideal gas assumes Z=1. Declared compressibility uses your starting/reserve endpoint Z values; intermediate pressure is not inferred.

Oxygen stage 100/0 · 7 L

Name

Display name. The immutable cylinder ID keeps physically distinct supplies separate.

O₂ · %

Oxygen fraction by volume. Nitrogen is the remainder after oxygen and helium. Composition alone does not establish suitability.

He · %

Helium fraction by volume. Oxygen plus helium must not exceed 100%.

Size · L

Start · bar gauge

Pressure above the site's ambient surface pressure. Converted to absolute pressure for the engine.

Reserve · bar gauge

Declared reserve pressure above ambient. Unmet reserve is a reported gas shortfall.

Volume convention

Ideal gas assumes Z=1. Declared compressibility uses your starting/reserve endpoint Z values; intermediate pressure is not inferred.

Exposure limits

Maximum CNS · %

Declared maximum predicted CNS fraction. A calculated exceedance remains an unmet constraint; this is not a personal medical limit.

Maximum accumulated OTU

Upper assessment bound for accumulated historical-model oxygen tolerance units, including retained prior exposure.

Maximum rolling 24 h OTU

Assessment bound for OTU within the preceding 24 hours. Unknown preceding exposure is shown as incomplete.

Breathing bounds

Minimum breathing PO₂ · bar

Declared lower bound for the breathed OC gas or applied CCR oxygen pressure along every segment. Hypoxic gases may require an explicit travel gas.

Maximum breathing PO₂ · bar

Declared upper bound for OC gas and applied CCR setpoint pressure. Separate from the CNS table, whose supported upper boundary is 1.6 ATA. Example value only.

Dive

Descent rate · m/min

Used to turn each profile waypoint's depth change into explicit travel time. Independent of model descent sampling.

Contingency

Calculates a separate retained-state OC exit at the end of the final bottom hold. Loss removes the selected cylinder; sharing applies your declared consumption multiplier.

About these options

None — Calculates a separate retained-state OC exit at the end of the final bottom hold. Loss removes the selected cylinder; sharing applies your declared consumption multiplier.

Gas Sharing — Calculates a separate retained-state OC exit at the end of the final bottom hold. Loss removes the selected cylinder; sharing applies your declared consumption multiplier.

Lose First Deco Gas — Calculates a separate retained-state OC exit at the end of the final bottom hold. Loss removes the selected cylinder; sharing applies your declared consumption multiplier.

Cylinder conventions

Delivery pressure margin · bar

Requires a conservative cylinder-pressure lower bound above greatest operating ambient pressure plus this margin. This is not a dynamic regulator simulation.

All values are explicit example inputs. Advanced options expose research conventions; unavailable engine combinations fail clearly.

THE DIVE, MOMENT BY MOMENT

40 m trimix exploration

∿

A CLEARER VIEW BELOW THE SURFACE

Build the plan.
Understand the dive.

Set your profile, equipment and model.
Then explore predicted loading, gas use and every stop on one shared timeline.

Model testing only · not to be used for planning real dives

40 m trimix exploration

Build the plan.Understand the dive.

Build the plan.
Understand the dive.