iOpenGTS vs Sailing Master M
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
iOpenGTS
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Save trip data on iPhone and synchronizes data with OpenGTS Trips can be selected by date range (by default, app shows the trips of current day); calendar shows the number of trips for each day. OpenGTS is not required, this app can work even without connection to an OpenGTS server ( and you can set connection even after you have registered many trips: as soon as OpenGTS is configured, iOpenGTS will start sending data that was not already sent) This app uses gps in background when tracking is active. Continued use of GPS running in the background can dramatically decrease battery life.
Sailing Master M
This app provides comprehensive sailing data and performance optimization on various Apple devices. It displays over 35 sailing measurements from boat instruments, polars tables, and nautical charts, offering detailed wind, route, and map views. Connectivity is established through NMEA 0183 Wi-Fi gateways.
- Configurable data displays
- 35+ sailing measurements
- Wind, route, and map displays
- NMEA 0183 Wi-Fi connectivity
- Polars table integration
- Nautical chart overlays
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Sailing Master M offers comprehensive sailing data and performance optimization information on iPhones, iPads, iWatches, and ActiveLook smart glasses. The application provides configurable pages and data displays, utilizing over 35 sailing measurements from the boat’s instruments, polars tables, and nautical charts. On phones and pads, the Data and Analog Displays can include minimum and maximum values and time series graphs. The Wind Display provides wind, heading, route, and speed information. The Route Display shows the expected wind conditions on the next legs. The Map Display shows the vessel with direction, tacking and downwind laylines on a nautical chart, or the wind laylines in another location. The connectivity is through NMEA 0813 Wi-Fi gateways such as B&G Vulcan, Zeus, GoFree, Yacht Devices, Signal K, Actisense, and ShipModul. The application has evolved from its initial focus on NMEA data display to encompass a comprehensive suite of features. Consequently, the app’s name has been revised from 'Display0183M' to 'Sailing Master M'. For further information, please refer to the user’s guide available on the app’s website or within the app itself. Terms of use: The app is delivered under the Apple End User License Agreement (EULA, https://www.apple.com/legal/internet-services/itunes/dev/stdeula/) The following libraries and services are used: - Kitura/BlueSocket, published under the Apache 2.0 license - A modified version of GPX package, published under BSD 3-Clause License and copyrighted by Ioannis Silks - OpenStreetMap licensed under the Open Data Commons Open Database License (ODbL, https://opendatacommons.org/licenses/odbl/) by the OpenStreetMap Foundation Licence, and ©OpenStreetMap contributors. OpenSeaMap, which is licensed under the Open Data Commons (ODbL) license, and ©OpenSeaMap contributors The supported NMEA 0183 sentences are: - BWR: Bearing and distance to waypoint - DBS: Depth below surface - DBT: Depth below transducer. - DPT: depth of water. - CGA: Global Positioning System Fix data - GLL: Geographic position Latitude/Longitude - HDG: Heading magnetic - HDM: Heading magnetic - HDT: Heading true - MWD: undocumented, wind direction, wind speed - MTW: water temperature °C - MWV: Wind speed and angle (A,T) - RMB: XTE, range to destination, bearing to destination, destination closing velocity . - RMC: Speed over ground - RSA: Rudder sensor angle - VHW: Water speed and heading - VLW: Distance travelled through water - VPW: Speed - measured parallel to wind - VTG: Course over ground (T or M), speed over ground - VWR: Wind direction (A), wind speed (A) - WCV: Waypoint closure velocity - XDR: air temperature (°C), water temperature (°C) and barometric pressure (mbar). - XTE: Cross track error The data items from NMEA and polars are: - Waypoint bearing - Waypoint distance - Time to Waypoint - VMG waypoint - Cross track error - Depth - Heading - Heading - Course - Course - Water speed - Speed over ground - Water temperature - Air temperature - Air pressure - Wind speed apparent - Wind angle apparent - Wind speed true - Wind direction - Wind direction - VMG Wind - Latitude, Longitude - Waypoint laititude, longitude - Water Distance after reset - Total water distance - Ground distance after reset - Total ground distance - Velocity made good towards wind - Heel - Rudder - Boat target speed through the water - Boat speed of target speed (%) - Beat VMG boat target speed through the water - Run VMG boat target speed through the water - GPS based trip distance - Leeway
Screenshots
Verdict
The clearest difference is ads: Sailing Master M at none against iOpenGTS's shown. Sailing Master M also leads on update cadence (every 2 months vs every 81 months). iOpenGTS's advantage is iOS requirement (11.0 vs 17). On price, in-app purchases 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. iOpenGTS sells 1 one-off in-app purchase and Sailing Master M sells 1 in-app purchase, starting at $11.99 per year. Whichever you choose, the download price is not the number that matters.
iOpenGTS ships an update every 81 months, Sailing Master M every 2 months. Both last shipped on November 11, 2026.
| Parameter | iOpenGTS | Sailing Master M |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (1 ratings) — better |
| Number of ratings | — | 1 — better |
| Update frequency | Every 81 months | Every 2 months — better |
| Ads | Yes | No — better |
| In-app purchases | Yes | Yes |
| Monetization | — | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Apple Watch |
| Requires iOS | 11.0 — better | 17 |
| Further details — not scored | ||
| Size | 30 MB | 25 MB |
| Age rating | 4+ | 4+ |
| Developer | 3B Soft srls | Pekka Leppanen |
In-app purchases
iOpenGTS
- OpenGTS adavanced features$2.99
Sailing Master M
- Pro annual14 Days trial$11.991 Year
Questions
Is iOpenGTS free?
Is Sailing Master M free?
Do iOpenGTS or Sailing Master M have ads?
Which is updated more often, iOpenGTS or Sailing Master M?
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