# Marinus vs GT Orcas

The clearest difference is in-app purchases: GT Orcas at none against Marinus's 1. GT Orcas also leads on ads (none vs shown) and iOS requirement (11.0 vs 13.0). Marinus's advantage is update cadence (every 5 weeks vs every 4 months). On price and device support there is nothing between them.

Both are free to download. Marinus sells 1 in-app purchase, starting at $8.99 per year. GT Orcas asks for nothing beyond the download.

Marinus ships an update every 5 weeks, GT Orcas every 4 months. The most recent releases landed on November 6, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | Marinus | GT Orcas |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (215 ratings)](https://appshunter.io/ios/app/marinus-maritime-rules/id536108872/reviews)** | — |
| Number of ratings | **215** | — |
| Positive reviews | 65.3% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Every 5 weeks** | Every 4 months |
| Monetization | Free with in-app purchases | — |
| Size | 113 MB | 59 MB |
| Requires iOS | 13.0 | **11.0** |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 17+ |
| Developer | [Alejandro](https://appshunter.io/developer/476976572) | [VANSIA SISTEMAS S.L.](https://appshunter.io/developer/914301017) |

## What reviewers say

### Marinus

[App page](https://appshunter.io/ios/app/marinus-maritime-rules/id536108872)

This app provides comprehensive guidance on maritime navigation rules and signals. It offers detailed information on flags, lights, sounds, and buoyage systems, along with interactive quizzes and a map feature. Designed for sailors, it ensures safe navigation on any vessel.

**Highlights:** Maritime flags and meanings, Weather scales and cloud identification, Sound signal guidance, Vessel navigation light diagrams, Day shape identification, Safe navigation maneuvers, Morse code decoder, IALA Buoyage System, Radio communication guidelines, COLREGs text

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Marinus PRO | $8.99 | per year |

**What reviewers like**

- 👍 Great app for learning
- 👍 Useful study aid
- 👍 Very helpful for mariners
- 👍 Good information provided
- 👍 Easy to use

**What reviewers complain about**

- 👎 Swamped with ads
- 👎 Broken app functionality
- 👎 Subscription model is a money grab
- 👎 Lifetime pro withdrawn
- 👎 Scam for changing to subscription

**Reported bugs**

- App not working, ads won't clear
- App crashes frequently
- Mistake with sounds
- App crashes after 10-15 seconds

**Requested features**

- Settings for Buoyage A & B & combined
- Search feature
- Combine sounds and lights
- Add tides information
- More free version functionality


### GT Orcas

[App page](https://appshunter.io/ios/app/gt-orcas/id6446023606)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Marinus free?

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

### Is GT Orcas free?

GT Orcas is free to download, with no in-app purchases.

### Do Marinus or GT Orcas have ads?

Marinus shows ads; GT Orcas does not.

### Which is updated more often, Marinus or GT Orcas?

Marinus ships an update every 5 weeks, and GT Orcas every 4 months. Most recently, Marinus was updated on November 6, 2026 and GT Orcas on November 3, 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.*