MAR vs Maritime Master
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
MAR
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These are datasheets of chemical substances developed by EMSA (European Maritime Safety Agency) that contain relevant information for responding to marine spill of hazardous and noxious substances (HNS). The MAR-CIS datasheets provide concise information on the substances' physical and chemical properties, handling and emergency spill response procedures, as well as maritime transport requirements for safe transport at sea. They collect different types of information on individual chemical substances: −Key properties: main hazards, and physical and chemical properties that define the emergency response operations from the very beginning e.g. flash point, vapour pressure; −Identification: reference numbers and names used to identify the substance; −Substance properties: main properties, appearance and behaviour; −Shipping information: explanatory information from the maritime transportation codes (e.g. IMDG, IBC and IMSBC codes) to help to understand how the substance is transported by sea and what responders can expect when they go on-board a vessel. Graphical representation of the GESAMP hazard profile; −Hazards and risks: classification and labelling, health and environmental hazards and substance intrinsic hazards; −Emergency measures: emergency health measures, emergency measures on board of vessels, exposure safety limits, environmental protection measures and danger zones for six different spill scenarios; −Case histories: past incidents involving the substances and response used; −Physical and chemical properties: the fingerprint of the substance. The application runs offline.
Maritime Master
This app provides a comprehensive suite of 88 professional maritime calculators for navigation, celestial observation, tides, stability, weather, engineering, and more. It's designed for maritime professionals and enthusiasts, offering offline functionality and citing all formulas with their official sources.
- 88 professional maritime calculators
- Offline functionality
- Navigation calculations
- Celestial observation tools
- Stability and cargo calculations
- Unit converters
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CalcDeck is the complete calculation toolkit for life at sea. It brings 88 professional maritime calculators into one beautifully designed iOS app, covering navigation, celestial observation, tides, stability and cargo, weather, engineering, safety, commercial voyage work, yacht and small craft performance, regulatory compliance and unit conversion. Whether you are a Master Mariner, deck officer, marine engineer, maritime cadet, yacht skipper or weekend sailor, CalcDeck replaces a shelf of reference books, a scratch pad and a pocket full of single-purpose apps. Every formula is cited with its textbook or IMO source, so you can verify the working and trust the result. CalcDeck is built by Maritime Master, the team behind COLREG Master, Nav Lights and IALA Buoyage, and is engineered to the same professional standard trusted by cadets and officers worldwide. What is inside Navigation (12 calculators): great-circle and rhumb-line distance, course to steer, ETA, set and drift, three-point fix, running fix, dead reckoning, cross-track error, waypoint bearing, speed-time-distance, departure and DMP, Mercator sailing. Celestial (8 calculators): sight reduction, meridian passage, altitude corrections, sunrise, sunset and twilight times, Polaris latitude, compass error by amplitude, azimuth of the sun, and chronometer error. Tidal (6 calculators): tidal height by the rule of twelfths, secondary port corrections, tidal streams, height at a given time, time at a given height, and clearance under bridges. Stability and Cargo (9 calculators): GM and list, trim and draft survey, free surface correction, deadweight and displacement, cargo load, block coefficient, TPC and MCTC, and final draft after loading. Weather (6 calculators): true wind, apparent wind, relative humidity, dew point, Beaufort scale conversion, and barometric trend. Engineering (10 calculators): fuel consumption and ROB, daily fuel burn, propeller slip, shaft power, specific fuel consumption, bunker density correction, trim tank transfer, admiralty coefficient, engine load, and voyage fuel planning. Safety (5 calculators): distance off by vertical sextant angle, horizon distance, dipping range, turning circle, and stopping distance. Yacht and Small Craft (5 calculators): hull speed, sail area to displacement, displacement to length, capsize screening, and ballast ratio. Commercial and Voyage (6 calculators): voyage cost, laytime, demurrage, freight rate per tonne, charter economics, and port disbursements. Regulations and Compliance (6 calculators): MARPOL discharge limits, SOLAS LSA requirements, STCW rest-hour compliance, load line zones, ballast water exchange, and garbage record categorisation. Unit Converters (12 calculators, all free): distance, speed, temperature, pressure, volume, mass, area, power, energy, angle, time and fuel. Every unit a mariner needs. Why CalcDeck CalcDeck works fully offline, so there is no signal, no signup and no interruption when you need an answer at sea. It is a native SwiftUI app designed for iPhone and iPad on iOS 17 and later, with a clean navy and gold Maritime Master design, dark mode support, favourites, and a Calc Pad that lets you pin your most-used tools for instant access on watch. There are no advertisements, no tracking and no subscriptions. Free and Pro You can try CalcDeck at no cost. All 12 unit converters and a selection of essential calculators in every professional category are included free. Unlock the full 85-calculator suite with a single one-time in-app purchase that is yours forever across all your devices. Who it is for CalcDeck is used by deck officers and Masters on coastal and ocean passages, by marine engineers calculating fuel, power and performance, by maritime cadets preparing for OOW, Chief Mate and Master examinations, by yacht skippers and RYA students, by cruising sailors, by pilots, harbourmasters and port operations staff, and by naval architects, surveyors and marine consultants.
Screenshots
Verdict
The clearest difference is in-app purchases: MAR at none against Maritime Master's 1. MAR also leads on iOS requirement (11.0 vs 17.6). Maritime Master's advantage is update cadence (daily vs every 9 months). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Maritime Master sells 1 one-off in-app purchase. MAR asks for nothing beyond the download.
MAR ships an update every 9 months, Maritime Master daily. The most recent releases landed on September 18, 2026 and September 23, 2026 respectively.
| Parameter | MAR | Maritime Master |
|---|---|---|
| Price | Free | Free |
| Rating | — | 3.0 (1 ratings) — better |
| Positive reviews | — | 0.0% of reviews |
| Number of ratings | — | 1 — better |
| Update frequency | Every 9 months | Daily — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Free |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 11.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 15 MB | 7 MB |
| Age rating | 4+ | 9+ |
| Developer | AG�NCIA EUROPEIA DE SEGURAN�A MAR�TIMA. | MARITIME MASTER LIMITED |
In-app purchases
MAR
No in-app purchases
Maritime Master
- CalcDeck Pro$14.99









