Dive Kit

Use this when the diver asks what gas to breathe at a depth or which deco gases to carry: returns the richest bottom mix within a PPO₂ limit (default 1.4 bar) and an END limit (default 30 m, 98 ft), the nearest standard fill inside the same limits, and the standard deco gas ladder for that depth with switch depths. Not for checking one named gas (gas_specs) or planning the dive (plan_dive). The ladder is the common choice, not a prescription: none to 30 m, EANx50 to 45 m, EANx50 and oxygen to 60 m, and a travel gas deeper. A bottom mix under 18% O₂ needs descent_gas in plan_dive. No engine call. Example: {"depth":50}

best_mix

Returns a diver's breathing rate measured from a logged dive: RMV (surface litres a minute, what plan_dive and gas_usage take) and SAC (pressure drop a minute on that cylinder), overall and per segment. Use this when a diver gives start and end pressures and asks their SAC, RMV or breathing rate. Give the cylinder's mix for trimix; air is assumed. Not for planning gas (gas_usage, plan_dive). Each segment is one stretch on one cylinder: depth, duration_min, start_pressure, end_pressure, the cylinder (preset, cylinder_size, rated_pressure, twinset; default AL80) and its mix (oxygen_pct, helium_pct; default air). RMV uses the same real-gas model as the planners: any RMV plans the same dive back to the measured end pressure in plan_dive, and an air RMV does in gas_usage, which assumes air (a trimix RMV reads about 1 to 2 bar optimistic there). SAC is the gauge drop over time and depth. Segments must not overlap in time; the tool cannot check that. sac is null when the segments used different cylinders, and sac_per_cylinder lists each, with the weighted average depth. plan_dive_gas_consumption.working_sac is ready to paste into plan_dive. water defaults to en13319. No engine call. Example: {"segments":[{"depth":20,"duration_min":20,"start_pressure":200,"end_pressure":140,"preset":"single_12l"}]}

rmv_sac

Returns the settings for continuous-flow blending through a compressor intake: each feed gas's share of the intake flow, the analyzer readings to aim for after the first injection and at the end, and the pressure to bleed to first when the cylinder's gas is in the way. Use this when a blender fills with fixed air, oxygen and helium feeds (a nitrox stick or membrane) and asks what ratios or analyzer targets give a mix. Not for partial-pressure fills (plan_blend). current is the cylinder now, as in plan_blend; target: oxygen_pct, helium_pct, pressure. injection_order he_first (default) or o2_first picks which intermediate analyzer reading the text leads with; both come back. bleed_step rounds the bleed down to a gauge mark, default 5 bar (100 psi). An impossible mix returns feasible false with the reason. No engine call. Example: {"current":{"oxygen_pct":21,"pressure":0},"target":{"oxygen_pct":32,"pressure":200}}

blend_continuous

Converts one diving figure between units: pressure (bar, psi, MPa), volume (L, ft³), depth (m, ft), temperature (°C, °F, K), weight (kg, lb) and breathing rate (L/min, ft³/min, bar/min, psi/min). Use this when a diver gives a figure in the other unit system or asks what it reads in another unit. Returns the converted value and the factor used. Not for depth to pressure (gas_specs) or a cylinder's capacity (lookup_cylinders). quantity names the kind; from and to take unit tokens: bar, psi, mpa; l, cuft; m, ft; c, f, k; kg, lb; l_min, cuft_min, bar_min, psi_min. Converting between a litres rate and bar_min or psi_min needs cylinder_size (water litres of the cylinder, both cylinders for a twinset), because a pressure drop per minute is litres only on one cylinder. Factors are Dive Kit's exact ones (1 bar = 14.5038 psi, 1 ft = 0.3048 m). No engine call. Example: {"quantity":"pressure","value":3000,"from":"psi","to":"bar"}

convert_units

Returns what happens when two cylinders are joined with a transfill whip: the pressure both settle to, each cylinder's pressure and mix afterwards, and how much gas moved. With a target mix it also returns where to close the valve, the mix the receiver reaches and what the donor keeps, or why the target is out of reach. Use this when a diver tops up one cylinder from another ("top my 50 bar EANx32 from a full EANx50") or asks whether a decant reaches a mix. Not for bank fills (plan_blend). receiver and donor as plan_blend's current: oxygen_pct, helium_pct, pressure, and preset or cylinder_size (default AL80 size). Gas flows from the higher pressure to the lower. The warm gas and the whip make the first gauge reading high: analyse after it cools. An unreachable target returns feasible false with the reason. No engine call. Example: {"receiver":{"oxygen_pct":32,"pressure":50,"cylinder_size":12},"donor":{"oxygen_pct":50,"pressure":200,"cylinder_size":12},"target":{"oxygen_pct":40}}

decant

Returns one section of the Dive Kit planning guide as markdown. Use this when you need to explain a term, a warning or deco theory, or to check what a planning conversation needs: workflow, tool chains, every input with unit, default and range (inputs_reference), deco theory, gradient factors, gas choice, gas planning, gas consumption, blending, weighting, CCR, bailout and contingencies, every warning, repetitive dives, worked examples, conventions, limits, sources; start_here is the index. Not for numbers: every figure comes from the planning tools.

get_guide

Finds the longest whole-minute bottom time on one level of an open-circuit plan: the longest that keeps every cylinder at or above its reserve (limit reserve), whose time to surface fits a budget (limit tts), or that needs no stop (limit no_deco). Use this when a diver asks how long they can stay at a depth before gas runs short, how long fits a TTS budget, or how long a level of a multi-level plan can last without stops. Not for CCR plans. For the no-stop time at one depth, check_no_deco is simpler. Takes the same fields as plan_dive, at the top level, plus the level to extend (default the deepest, last on a tie; the same level longer_3min lengthens). Cylinders as in plan_dive. On a level shallower than an earlier one the answer can be a window ("from 7 min"). The empty-cylinder setting is ignored: every cylinder is judged on its own reserve. The answer is a gas ceiling with no allowance for gas sharing, cold, current or work. Returns the answer, the plan table at that time and its Dive Kit share link. Units and defaults as in plan_dive. Example: {"plan_name":"45m on 21/35","units":"metric","levels":[{"depth":45,"bottom_time_min":20}],"cylinders":[{"id":"back","oxygen_pct":21,"helium_pct":35,"preset":"twin_12l","start_pressure":220},{"id":"deco","oxygen_pct":50,"preset":"stage_11l"}],"limit":"reserve","level_number":1}

find_max_bottom_time

Returns the facts for one breathing gas: maximum operating depth (MOD) at its Dive Kit PPO₂ band cap and at 1.4 bar, minimum depth for hypoxic mixes and, at a depth, PPO₂, equivalent narcotic depth (END), equivalent air depth (EAD) and gas density. Use this when the diver asks whether a gas is OK at a depth, its MOD, END, EAD or density. Not for planning a dive (plan_dive) or picking a gas (best_mix). Mixes are O₂ % and He %; depth follows units. The band cap is 1.4 bar under 28% O₂, 1.5 to under 45%, 1.6 at 45% and over, unless ppo2_max is given. No engine call. Example: {"oxygen_pct":32,"depth":35}

gas_specs

Returns the gas one open-circuit cylinder spends over a planned profile: per segment the gas used (volume and pressure), what is left, the runtime and a status, plus the reserve, the turn pressure and the first segment that drops below each. Use this when a diver asks whether a cylinder covers a no-stop or multilevel dive, how much gas a dive uses, or their turn pressure. Not for decompression dives (plan_dive charges deco gas) or measuring a breathing rate (rmv_sac). sac is the surface breathing rate in L/min (ft³/min imperial), default 20; rmv_sac's rmv and plan_dive's gas_consumption.working_sac are the same figure. Cylinder fields as in plan_dive (preset, cylinder_size, rated_pressure, twinset, start_pressure); default one AL80 at 3000 psi (206.84 bar). reserve as in plan_dive (thirds; fixed defaults to 50 bar, 725 psi). water defaults to en13319; altitude (m or ft) defaults to sea level. Real-gas volumes; the cylinder is assumed to hold air (plan_dive takes any mix). No engine call. Example: {"preset":"al80","segments":[{"depth":18,"duration_min":40},{"depth":5,"duration_min":3}]}

gas_usage

Returns diving certifications from Dive Kit's vetted open dataset of agencies and courses: prerequisites, equivalent courses at other agencies, depth and gas limits, notes and links. Use this when a diver asks what a course allows ("what does PADI Tec 45 let me do"), what they need before a course ("what do I need before a trimix course"), whether two courses are equivalent ("is SSI X equivalent to PADI Y"), or what an agency offers. Not for planning a dive. This is Dive Kit's own curated data (CC BY 4.0, open.divekit.app), not a web search; agency rules change, so point the diver to the agency for the final word. No engine call. Example: {"agency":"PADI","query":"tec 45"}

lookup_certifications