# OpenSeaMap vs Sailing Master M

The clearest difference is rating: Sailing Master M at 5.0 against OpenSeaMap's 1.0. On price, ratings volume, update cadence and ads there is nothing between them.

Both are free to download. OpenSeaMap 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.

Sailing Master M holds the better App Store score, 5.0 against 1.0. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on October 21, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | OpenSeaMap | Sailing Master M |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.0 (1 ratings)](https://appshunter.io/ios/app/openseamap/id495210783/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/sailing-master-m/id1566599912/reviews)** |
| Number of ratings | 1 | 1 |
| Positive reviews | 38.3% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | Every 2 months |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 13 MB | 25 MB |
| Requires iOS | 18.6 | **17** |
| Devices | iPhone, iPad | **iPhone, iPad, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [appdoctors UG](https://appshunter.io/developer/961029450) | [Pekka Leppanen](https://appshunter.io/developer/1566599914) |

## What reviewers say

### OpenSeaMap

[App page](https://appshunter.io/ios/app/openseamap/id495210783)

This app provides a free, worldwide nautical chart with detailed sea information, including lights, weather data, and harbor details. It offers chartplotting, waypoint management, and offline map caching for navigation. Users can mark locations, enter coordinates, and adjust chart zoom for optimal viewing.

**Highlights:** Free worldwide sea chart, Chartplotting with tracking, Waypoint creation and export, Offline map caching, Mark and search locations, Adjustable chart zoom

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| OpenSeaMap Professional | $1.99 | one-time |


### Sailing Master M

[App page](https://appshunter.io/ios/app/sailing-master-m/id1566599912)

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.

**Highlights:** Configurable data displays, 35+ sailing measurements, Wind, route, and map displays, NMEA 0183 Wi-Fi connectivity, Polars table integration, Nautical chart overlays

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro annual | $11.99 | per year |


## Frequently asked questions

### Is OpenSeaMap free?

OpenSeaMap is free to download, with in-app purchases available.

### Is Sailing Master M free?

Sailing Master M is free to download, with in-app purchases available.

### Which has better reviews, OpenSeaMap or Sailing Master M?

Sailing Master M is rated higher. OpenSeaMap averages 1.0 out of 5 from 1 ratings, while Sailing Master M averages 5.0 from 1 ratings.

### Do OpenSeaMap or Sailing Master M have ads?

Neither OpenSeaMap nor Sailing Master M shows ads.

### Which is updated more often, OpenSeaMap or Sailing Master M?

OpenSeaMap ships an update every 2 months, and Sailing Master M every 2 months. Most recently, OpenSeaMap was updated on October 21, 2026 and Sailing Master M on October 13, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*