Neptune vs Master
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Neptune
Prepare for USCG COLREG and OOD exams with a comprehensive study system. Features AI tutoring, interactive 3D visuals for lights and shapes, and a complete question bank with intelligent test modes and progress tracking.
- AI-powered tutor for rule explanations
- Interactive 3D lights and shapes trainer
- Official USCG question bank
- Verbatim memory trainer
- Intelligent exam simulator modes
- Advanced progress tracking
- Offline study capability
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PASS YOUR USCG COLREG & OOD EXAMS WITH CONFIDENCE Neptune: Navigation Rules is the only modern study system that combines the official USCG Question Bank with an AI Tutor, interactive 3D Visual Training, and verbatim cards. Whether you are an Ensign preparing for OOD Phase 1 or a Captain refreshing for a renewal, Neptune replaces heavy textbooks with a smart, pocket-sized coach. NEW: VERBATIm MEMORY TRAINER Level up recall: hide key phrases and type them back to prove you know the rule, not just the letter. Adaptive drills: auto-submit when blanks are filled, with instant feedback and retries to lock in weak spots. Inline citations: jump straight from a missed phrase to the exact rule text. 3D LIGHTS & SHAPES TRAINER Stop memorizing static flashcards. Interactive 3D Models: Rotate vessels to see lights and shapes from any angle. Quiz Mode: Answer questions based on target angle, vessel ID, cardinal direction, and rules of the road. AI-POWERED REFERENCE Don't just memorize the answer—understand the Why. Ask Neptune: Chat with an AI trained specifically on COLREGS and over 500 maritime court cases. Instant Explanations: Get plain-English breakdowns for every question with citations to the rules and cases. Legal Context: Using the court cases see how rules are adjudicated in the real world. COMPLETE USCG QUESTION BANK & BOOK Official Pool: Full access to Inland and International questions. Smart Citation: Every question is linked directly to the specific Rule it tests. Custom Tags: Add your own notes, highlights and rule references. INTELLIGENT TEST MODES Exam Simulator: Mimic the real test by creating presets with precise filters for question number, specific words to be omitted, and rules. Or enable the Smart algorithm to dish you out trouble questions. Study Mode: Filter by "Least Confident" to drill the questions you get wrong. Daily Challenges: Keep your streak alive with quick, timed quizzes to build a daily study habit. ADVANCED PROGRESS TRACKING Confidence Scores: Visualize your mastery of every Rule based on SM-2 Algorithm. Heat Maps: Instantly see if you are weak on "Steering & Sailing" or "Sound Signals." Detailed History: Review past attempts to track your improvement over time. THE MODERN STANDARD Offline Ready: Study in the SCIF or underway—no internet required. Dark Mode: Fully optimized for night watch study sessions. Cloud Sync: Start on your iPhone, finish on your iPad.
Master
Practice maritime navigation rules and buoyage systems with this app. It helps you identify knowledge gaps and track your progress in mastering essential regulations for mariners.
- USCG Navigation Rules practice
- IALA Maritime Buoyage System tests
- Knowledge gap identification
- Progress tracking
- Developed by Master Mariner
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Master-Nav: COLREGS IALA Tests is a free practice app developed by a Master Mariner with 30 years of seagoing experience. Test your knowledge of the USCG Navigation Rules and IALA Maritime Buoyage System — the regulations every mariner needs to know. A straightforward way to find out where you stand, identify gaps in your knowledge and track your progress over time. Master COLREGS & IALA — the easy way.
Screenshots
Verdict
The clearest difference is update cadence: Neptune at every 4 days against Master's fortnightly. Neptune also leads on ratings volume (17 vs 1) and device support (3 vs 1). On price, rating, review sentiment and ads 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. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 5.0 for Neptune against 5.0 for Master. That said, the two scores are not equally well evidenced: Neptune has 17 ratings behind it against 1, so its average is the more settled of the two. Written reviews split almost evenly too, at 100% and 100% positive.
Neptune ships an update every 4 days, Master fortnightly. Both last shipped on October 25, 2026.
| Parameter | Neptune | Master |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (17 ratings) | 5.0 (1 ratings) |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| Number of ratings | 17 — better | 1 |
| Update frequency | Every 4 days — better | Fortnightly |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 96 MB | 305 MB |
| Age rating | 4+ | 4+ |
| Developer | Brice Brown | Peterjohn Chisholm |
Customer experience
Neptune
Master
In-app purchases
Neptune
No in-app purchases
Master
No in-app purchases









