Innehåll

Deco engine

MultiDeco test results

Pick a scenario and compare the Dive Kit deco engine against the MultiDeco mobile app, side by side. MultiDeco is a mature planner that many divers trust, and we use it as a second opinion rather than an answer key. Every scenario behind the how Dive Kit compares to MultiDeco write-up is published here in full, so you can check the numbers yourself.

Vi jämför mot mobilappen MultiDeco (iOS och Android), en planerare som används mycket inom teknisk dykning. Varje MultiDeco-siffra här kommer från den mobilappen. Vi har inte testat skrivbordsversionen, så vi gör inga påståenden om den. Identiska siffror är inte målet: två motorer med samma modell skiljer sig lite på bedömningsfrågorna ovan, så syftet är att vara överens om fysiken som spelar roll och att förklara varje skillnad. För att ställa de två i linje kör Dive Kit-kolumnen i avrundat läge (heltalsminuts-stopp) för varje scenario, eftersom MultiDeco också visar hela minuter. Gastätheten är den enda avläsningen som beror på temperaturen: Dive Kit räknar den vid vattentemperaturen i din plan, och varje scenario här kör på standardvärdet 15 °C. Version 2.9.0 förankrade Dive Kits gradient factor-linje vid det exakta djup dina vävnader når i stället för vid 3 m-stoppet ovanför, vilket drar åt linjen vid varje grundare stopp. Det slöt gapet på två storheter och öppnade det något på en tredje. Första stoppet steg ett 3 m-steg djupare i fyra scenarier, alla fyra mot MultiDeco, medan 22 inte flyttade sig och inget flyttade sig bort. Total dekompressionstid flyttade sig mot MultiDeco i alla 14 scenarier där den ändrades. Tid till ytan krympte i sex och växte i åtta, eftersom Dive Kit i sex av de åtta redan gick längre än MultiDeco, så mer dekompressionstid sköt den ännu längre ut. Version 2.10.0 ändrade var den linjen hänger på ett flernivådyk. Den hänger nu från det djupaste taket under hela bottenfasen i stället för från det tak som råkade stå när uppstigningen började, så en plan vars sista nivå är grundare än en tidigare visar 1 till 5 minuter mindre dekompression än i 2.9.x, medan planer med en enda nivå är oförändrade. Det flyttade de två flernivåscenarierna här, A1 och P1, en minut var närmare MultiDeco: A1:s tid till ytan är nu lika med MultiDecos 22 minuter, och P1:s första stopp står nu på 24 m mot MultiDecos 27 m, ett 3 m-steg, där det tidigare stämde överens. Vi publicerar varje scenarios indata, MultiDecos utdata och Dive Kits utdata nedan, och samma scenarier körs i vår automatiserade testsvit, så en ändring som flyttar de här siffrorna syns i våra tester.

S1

Air 30 m / 23 min, GF 30/70 (salt)

Decozon inom 1 dekosteg O₂-klocka matchar
Öppna planen i Dive Kit

Skapad med Dive Kits motor v2.2.7. Länken laddar exakt samma indata, så appen återskapar tabellen du ser här. En senare appversion kan ändra en siffra något; vi håller de här sidorna aktuella så gott vi kan.

Dyket

ett dyk · två planerare

30 m × 23 min · Air

Gradient factors
30/70
Vatten
Salt
Sista stopp
3 m
Gaser
Air
▸ Hur varje app konfigurerades

MultiDeco

  • Bottentid inmatad 25 min (inklusive nedstigning)
  • Uppstigning 9/6/3 m/min (djup/deco/yta)
  • Bottengas fastställd per profilsteg; decogaser listade separat

Dive Kit

  • Bottentid på djup (nedstigning räknas separat)
  • Tvåtakts-uppstigning 9/3 m/min, växlar vid 3 m
  • Profil + gaslista hålls separat; decogas autovald via MOD

Samma fysiska dyk, inmatat i varje verktygs egen stil. Det är därför några siffror är fördelade annorlunda medan fysiken är överens.

Mått MultiDeco Dive Kit Δ Överensstämmelse
Decozon-start (m) 21 20.7 -0.3 matchar
Första stopp (m) 12 12 0 matchar
Tid till ytan (min) 22 24 +2 matchar
CNS (%) 6 6 0 konservativ
OTU 18 18 0 konservativ
Gasdensitet (g/L) 4.8 4.9 +0.1 konservativ

Ett ✓ betyder inom den dokumenterade toleransen för det måttet. ”≈” markerar en medveten, förklarad skillnad (t.ex. stoppfördelning, eller Dive Kits mer konservativa O₂-klocka). Se Varför de skiljer sig nedan; det är aldrig ett fel.

▸ Fullständiga scheman stopp för stopp

MultiDeco

DjupStoppKörtidGas
12 m1 min2821
9 m3 min3121
6 m4 min3521
3 m11 min4621

Dive Kit

DjupStoppKörtidGas
12 m3'30'21
9 m4'34'21
6 m6'41'21
3 m7'48'21

Varför de skiljer sig

En ren matchning. Skillnaderna här är de vanliga dokumenterade konventionerna (stoppfördelning och gasdensitetens referensförskjutning). Se de delade förklaringarna.

Skillnaderna, förklarade en gång

Varje notering per scenario i visaren pekar tillbaka på en av dessa delade förklaringar.

Matchning av uppstigningstakt Vi kör Dive Kit med samma uppstigningshastigheter som vi använde i MultiDeco, så jämförelsen blir rättvis. Den djupa hastigheten som sätter första stoppet är 9 m/min i båda.

Dive Kit och MultiDeco stiger med samma hastigheter i de här körningarna. Den hastighet som avgör var ditt första stopp hamnar är den djupa uppstigningen, från botten upp till första stoppet, och den är 9 m/min i båda verktygen, så den delen är en jämförelse på lika villkor. På S- och FS-dyken rör sig MultiDeco lite långsammare mellan de grundare stoppen (6 m/min) än vad Dive Kit gör, men det ändrar inte var första stoppet hamnar. Vi testade detta direkt: skillnaden i första stoppet är densamma när vi matchar den djupa hastigheten, så den kommer från hur Dive Kit räknar om dina vävnader medan du stiger, inte från att stiga fortare eller långsammare (se general/stopDistribution).

Decozon-start Decozone start is GF-independent by design. On a single-level dive it matches MultiDeco within about one deco step; on a multi-level dive that ends shallow the two read very differently, because they are measured at different moments. That is a definition difference, not a model error.

Dive Kit computes a 'decozone start', the depth where your decompression obligation begins. We use it here as a clean cross-check; it is not shown in the app. It is the deepest depth where a tissue's total inert-gas pressure (nitrogen plus helium) passes the surrounding pressure, and it does not depend on your gradient factors, because gradient factors move the M-value line, not the ambient line. You can see this in the data: S2 (GF 30/70) and S7 (GF 50/80) are the same 45 m / 22 min air dive and both show 32.3 m, even though their first stops differ (21 vs 15 m). On the single-level scenarios Dive Kit lands within about one 3 m step of MultiDeco, at most 3.6 m, on the deepest high-helium CCR dive, C3. The multi-level scenarios split into two groups, and the split says exactly what the difference is. Dive Kit reads the decozone from the tissue state at the END of the bottom phase; MultiDeco appears to read it at the deepest point of the dive. Where the dive ends deep the two agree: W4 finishes on a 40 m level and reads 25.8 m against 25 m. Where it ends shallow they do not, because the shallow level has already off-gassed the fast compartments by the time Dive Kit measures: P1 reads 35 m against 45 m, W1 18.6 m against 50 m, W2 24.4 m against 58 m, W3 17.4 m against 45 m, W7 15.2 m against 21 m, and W5, whose last level is 6 m, 7 m against 28 m. None of this moves a stop. The operational first stop on those same dives is at most one 3 m step apart, 24 m against 27 m on P1 and 18 m against 21 m on W3.

Stoppfördelning Dive Kit's first stop can be shallower than MultiDeco's. The total decompression is close; it just sits at different depths.

MultiDeco lists a short stop at almost every 3 m step from the deepest stop up, often well under a minute. Dive Kit holds fewer, longer stops and skips the deepest ones, so its first listed stop is shallower (S6: 39 vs 48 m; S5: 30 vs 33; FS5: 24 vs 27). Both tools agree on the deepest depth where you owe a stop. They differ on the way up: Dive Kit recomputes all your tissues every second as you climb, the way the computer on your wrist does, so it counts the gas you breathe off during the climb itself. Helium leaves the fast tissues quickly, so on a helium dive the ceiling drops faster than you climb, and there is nothing to stop for in those first few metres. The gap is biggest on deep, high-helium dives (9 m on S6, C3 and A2, 3 m on S5 and FS5) and at most one 3 m step on air and nitrox. The total time to surface stays within a few minutes either way (S6 85 vs 81, S5 48 vs 45, FS5 43 vs 42, A2 55 vs 56), and Dive Kit's leading tissue still reaches the surface exactly at your GF-High, so it never shortcuts your decompression. Compare total time to surface, not the depth of the first stop. The gap narrowed in 2.9.0: Dive Kit now anchors its gradient factor line at the exact depth your tissues reach rather than at the stop above it, which tightens the line at every shallower depth. What that moved, quantity by quantity. First stops stepped one 3 m level deeper on four scenarios, every one of them toward MultiDeco (S6 36 to 39 m, S5 27 to 30, FS5 21 to 24, A3 24 to 27); the other 22 did not move, and none moved away. Total decompression time moved toward MultiDeco on all 14 scenarios where it changed at all, and the remaining 12 stayed where they were. Time to surface is the mixed one: it narrowed on six (A4, A5, A6, FS2, FS5, S7) and widened on eight (S5, S6, FS1, FS4, A1, C1, G1, P1). Widening is what you would expect there. On six of those eight Dive Kit's time to surface already sat above MultiDeco's before the change, so adding decompression time pushed it further out (S5 from 0.3 to 2.3 min above, S6 from 1.6 to 3.6). On A1 the two matched exactly and Dive Kit now runs a minute longer; on C1 Dive Kit sat 0.2 min under and now runs 0.8 over. A dive with a long 6 m last stop is still the axis where Dive Kit holds the 6 m stop shorter (see A4 and A5); since ENGINE_VERSION 18 that still makes A5 finish sooner, while on A4 the extra time at the deeper stops outweighs it.

CNS-grund (omgivande ppO₂) Dive Kit uses ambient ppO2 for CNS (the NOAA limits with Baker's ambient-pressure method).

CNS oxygen-toxicity % is accumulated against the NOAA exposure limits using the AMBIENT ppO2 (fO2 x absolute pressure), with no alveolar water-vapour subtraction. This is Erik Baker's published method and matches Shearwater, Garmin and Subsurface; it reads slightly higher than a water-vapour-reduced value. It runs ~1-3% higher than MultiDeco on most dives, and noticeably higher when a high-ppO2 deco gas sits right at a steep bracket of the NOAA curve (see S6).

Gasbytesgränser Each gas switches at a depth set by its oxygen content (caps 1.4/1.5/1.6 bar). These match MultiDeco's switches within one stop.

Dive Kit caps each gas by its oxygen content: a lean mix (under 28% oxygen) at 1.4 bar, a mid mix (28 to 45%) at 1.5, a rich mix (45% or more) at 1.6. The same cap sets both the switch depth and the hyperoxia warning. MultiDeco caps gases the same way, so at its default 1.4/1.5/1.6 the switches on the single-level scenarios match exactly: Tx21/35 at 57 m, Tx35/25 at 33 m, EAN50 at 21 m and oxygen at 6 m. Until ENGINE_VERSION 18 Dive Kit took the first two one stop shallower (54 and 30 m), because it would not let a gas sit even slightly over its cap; it now counts a gas as breathable while its ppO2 is at most 0.03 bar over the cap, which also keeps the 6 m oxygen stop (1.62 bar in salt) usable in every water type. The multi-level P1 is the exception: Dive Kit takes its Tx35/25 at 33 m and MultiDeco at 27 m.

Nivåer och taket Version 2.10.0 removed the line between the bottom phase and the decompression phase. A dive level placed shallower than the current ceiling is now reached by running the decompression down to it, and a gas change between two levels happens where that gas is safe to breathe.

Before 2.10.0, an ascent between two of your own dive levels was a plain two-stage ascent with no ceiling check, and the decompression phase only started after the last level. A level planned above the current ceiling was therefore reached by flying through every stop owed on the way. Those stops are now woven into the dive: the engine plans that ascent properly, inserting the stops between the two levels and making the gas switches those stops call for, and the level's own gas takes over on arrival. A profile point can sit anywhere, including inside the decompression. Which gas an inter-level leg is breathed on follows one rule in both directions. Going deeper you switch before you descend, at the depth you are already at, because the deeper level's gas is the leaner one and there is no later moment at which it could safely be taken up. Coming shallower you ascend on the gas you are already breathing and switch when you arrive, because the shallower level's gas is the richer one and is only safe once you are shallow. At the same depth you switch in place. The gas switch time is spent where the switch happens, on the gas you are leaving. The W series is built on exactly this: W1 through W6 each place a level shallower than the ceiling standing at the end of the leg before it, and W7 is the control that does not. MultiDeco was captured on six of the seven in September 2026, and it weaves too. On W2, W3 and W5 it inserts the owed stops in front of the level exactly as Dive Kit does, starting at the same 36 m on W2. Where it differs is which gas those stops are breathed on: MultiDeco holds the gas the diver was already on until the level is reached, while Dive Kit takes the next mix up at the depth where that mix first meets its ppO2 cap, which shortens the woven stops and raises the oxygen exposure. The mirror case is W4's descent back to 40 m: Dive Kit swaps off the EANx50 at 21 m before going down, MultiDeco carries it to 40 m and reads 96 % CNS for the dive against Dive Kit's 42 %. W6, the rebreather scenario, weaves in both tools as well, holding its two pre-level stops on the loop at the dive's setpoint rather than switching off it, and Baltic, the third planner captured on W6, weaves there too, holding three pre-level stops on the loop in the same way and starting them one stop deeper. Every other scenario here, the A, S, FS, C, P, G and R series, reaches each level with an ordinary ascent and no table of theirs moves with this change.

Gasdensitet Gas density is computed at your plan's water temperature, 15 °C by default. Before rounding, Dive Kit reads 2.1 to 4.1 percent above MultiDeco across every scenario MultiDeco has been run on, averaging about 3.

Gas density tells you how hard the gas is to move through your airways. It is a reference reading, not an output of the decompression model. Dive Kit scales the ideal-gas figure by the water temperature in your plan's Environment settings, because a colder gas is denser, and the default is 15 °C (59 °F), the EN/ISO reference the app already uses for its real-gas cylinder tables. Every density figure in these tables is computed at that default, and printed to one decimal place, as the app prints it. Measured against MultiDeco across all 33 scenarios that have a MultiDeco density capture, Dive Kit's unrounded figure reads between 2.1 and 4.1 percent higher, averaging about 3 percent, and it is the higher of the two on every single one. The narrowest gap is A3, 5.3 g/L against 5.2, and the widest is A1, 4.8 against 4.6; the deepest reading in the set is A6 at 8 against 7.7. About half a point of that gap is new in ENGINE_VERSION 18, which converts depth to pressure with the physical water density: salt water at 9.95 m per bar and fresh water at 10.20 read a little more pressure at the same depth than the old 10.0 and 10.3, so every density here rose by 0.2 to 0.9 percent. Part of that spread is simply MultiDeco reporting density to one decimal place. Before version 2.9.0 Dive Kit fixed the reference at 0 °C, which read 7 to 9 percent above MultiDeco, so every figure here is about 5 percent lower than the 2.8.7 tables. The two limits did not move with it: 5.2 g/L for the caution and 6.2 g/L for the critical flag are published figures (Anthony and Mitchell, 2016), not model outputs, so a warmer reading reaches them a little deeper. Five scenarios changed how they are flagged as a result: S4, FS4 and A2 drop from critical to caution, and FS3 and FS5 fall below the caution line entirely. ENGINE_VERSION 18 puts FS3 back over it, at 5.3 g/L, for the fresh-water reason above; FS5, at 5.1, stays under. Temperature affects the density reading and the warning that hangs off it, and nothing else. The Bühlmann model has no temperature term, so not one stop time in these tables moves with it.

Gasförbrukning (liter) Litres used depend on your breathing rate, so this is not a comparison of the deco math. Rebreather bailout now splits across two rates.

Gas consumption depends entirely on the breathing-rate (SRMV/SAC) settings, which are a user preference and not an output of the decompression model. Dive Kit's figures here use 20 L/min working and 15 L/min deco, so absolute litres differ from a MultiDeco run configured with a different SAC. Match the rates before comparing litres. From version 2.9.0 an open-circuit bailout off a rebreather is charged in two phases instead of one: the leg from the depth you bail out at down to the first deco stop runs at your Working SRMV, because swimming up off the loop is work, and everything from the first stop onward runs at your Deco SRMV. That is MultiDeco's own convention. It raises the bailout gas figure and leaves the schedule untouched. None of the 26 scenarios here carries a bailout cylinder (the three CCR dives are pure loop decompression at a constant setpoint), so the split changes no number in these tables. Also from 2.9.0, the minute the diver spends purging a regulator when the profile changes gas between levels is billed to the cylinder they switch to, at the Working SRMV, instead of being dropped: the tissue model always counted that minute, and now the gas tally does too. Only P1 changes a number here, because it is the only scenario whose levels change cylinder (a travel-gas descent that switches from Tx35/25 to Tx18/45 at 30 m), and its Tx18/45 figure rose by 79 L, from 3985 L to 4064 L, or 3 bar. Every schedule was unchanged. ENGINE_VERSION 18 then moves P1's switch onto Tx35/25 from 30 to 33 m (see P1), and the Tx18/45 figure settles at 4054 L.

CCR-slingdeco CCR (rebreather) loop deco matches MultiDeco closely. CNS and OTU are near-exact, decozone within a step.

Pure-loop CCR deco (constant setpoint 1.3, no open-circuit switches) holds up well across air, trimix and deep high-helium diluents (C1 to C3): CNS within 1 percentage point (28/27, 38/37, 54/53), OTU within 5 units (73/70, 102/99, 145/140), and time to surface within a minute (20/19, 45/44, 79/78, Dive Kit's rounded up to the next whole minute). Decozone is within one 3 m step except on the deep 80 m high-helium dive C3 (65.6 vs 62, the same wider spread seen on the deep trimix dive S6). The first listed stop is shallower than MultiDeco, the usual stop-distribution effect on a helium diluent (see general/stopDistribution). Gas density runs about 3% higher, the usual water-temperature offset (see general/gasDensity). CCR is also covered by our automated tests.

Nya indata till motorn Version 2.9.0 gav motorn tre nya planerarindata och en ny utdata. Alla ligger på sina standardvärden i de här körningarna, så bara vattentemperaturen rör en publicerad siffra.

Korsreferensen kör varje scenario med de nya indata på sina levererade standardvärden, så du läser fortfarande samma dyk som de tidigare tabellerna beskrev. Fördröjning före uppstigning är ett håll på det djup uppstigningen startar från, för de minuter det faktiskt tar att reda ut ett problem innan man lämnar botten. Det är verklig tid på djupet: vävnaderna fortsätter ladda, CNS och OTU fortsätter räknas, och tiden till ytan växer. Standardvärdet är ingen fördröjning alls, så varje scenario här går upp direkt. Stressfönstret är en höjd andningsförbrukning under en bestämd sträcka från det att problemen börjar, eller hela vägen till ytan. Det ändrar bara gasberäkningen och flyttar aldrig ett stopp. Det är avstängt som standard. Vattentemperaturen matar täthetsavläsningen och ingenting annat, och varje scenario kör på standardvärdet 15 °C (se general/gasDensity). Det fjärde tillskottet är en utdata snarare än en indata: motorn rapporterar nu återstående nolltid vid slutet av varje nivå, avläst vid planens GF-high. MultiDecos inspelningar har ingen motsvarande siffra, så jämförelsetabellerna nedan visar den inte; den finns i appen och i motorns maskinläsbara utdata.

conventions Planners that use the 1 bar = 10 m convention read MOD and switch depths slightly differently; Dive Kit uses 1.01325 bar and physical water density (see Conventions).

Dive Kit converts depth to pressure from the real surface pressure (1.01325 bar at sea level, lower at altitude) with metres per bar derived from water density and g: fresh 10.20, EN 13319 10.00, salt 9.95, Red Sea 9.92. A gas counts as breathable while its PPO₂ is at most 0.03 bar over its cap, and the MOD it reports is the exact depth where the PPO₂ meets the cap. Where a note here quotes a Dive Kit figure next to another planner's, that difference is part of what the two numbers measure. Dive Kit's figures are printed the way the app prints them: run time, time to surface, decompression time and every Run value rounded up to the next whole minute (never shorter than the plan), CNS and OTU to the whole number, gas density to one decimal. The other planners' figures are the ones those planners show.

Kör det själv

Du behöver inte ta vårt ord på något av det. Mata in dessa exakta scenarier i Dive Kit och i mobilappen MultiDeco och jämför dem mot siffrorna ovan. Vi publicerar hela datamängden här: varje scenarios indata, båda verktygens utdata, och noteringarna per scenario. Båda kolumnerna visar heltalsminuts-stopp, eftersom Dive Kit-kolumnen kör i avrundat läge, som är appens standard. Så appen visar dig dessa samma siffror. (Ställ om appen till precist läge så löses stoppen upp till sekunden, men total tid till ytan håller sig inom en minut eller två.)

Koppla samman de fyra filerna via scenario-id. Dive Kits motor är proprietär, men varje utdata här är reproducerbar genom att köra samma dyk i appen. Jämförelsen står på data, inte på tillit.

The full write-up covers how the cross-check is run, where the two planners agree and differ, and a step-by-step trace of the deep-stop difference: see How Dive Kit compares to MultiDeco.

Delar av den här guiden har skrivits med AI-hjälp och kan innehålla fel. Den är utbildande, inte en ersättning för utbildning. Dyk alltid inom ramen för din certifiering och verifiera med dina instrument.