Neptune vs CA'Sim
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.
CA'Sim
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Transform your device into a professional radar simulator and collision avoidance training tool. CASim is designed for maritime cadets, deck officers, and navigation enthusiasts who want to master the International Regulations for Preventing Collisions at Sea (COLREGs) through practical application. Bridge the gap between theory and reality. Practice identifying risks on the radar scope, correlating them with visual aspects, and executing the correct maneuvering actions. Key Features: - Realistic Radar Simulator: Experience a fully functional Head-Up radar scope complete with variable range scales, target trails (history), and relative motion vectors. - Tactical Plotting (MoBoard): Integrated digital Maneuvering Board. Plot targets manually or automatically to calculate CPA (Closest Point of Approach), TCPA, and determine the precise course to steer to avoid collisions. - Visual Aspect Visualization: See what the target ship looks like in reality. The app generates 3D models with correct Navigation Lights (Night) and Day Shapes based on the target’s aspect angle. - Restricted Visibility Mode: Simulate fog conditions (Rule 19). Test your ability to navigate using only radar and sound signals. - Sound Signals: Authentic fog signals (Rule 35) are generated automatically based on the vessel type and status (Underway, Stopped, NUC, Anchored, etc.). - Custom Scenarios: Create your own traffic situations with multiple targets, varying speeds, and ship types to challenge your skills. Whether you are preparing for your competency exams or refreshing your skills, CASim provides the most comprehensive simulation environment right in your pocket. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is in-app purchases: Neptune at none against CA'Sim's 4. Neptune also leads on iOS requirement (15.0 vs 18.6). On price, update cadence, 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. CA'Sim sells 4 in-app purchases, starting at $0.99 per month. Neptune asks for nothing beyond the download.
Neptune ships an update every 4 days, CA'Sim weekly. The most recent releases landed on October 10, 2026 and October 11, 2026 respectively.
| Parameter | Neptune | CA'Sim |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (15 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 15 — better | — |
| Update frequency | Every 4 days — better | Weekly |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.0 — better | 18.6 |
| Further details — not scored | ||
| Size | 96 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | Brice Brown | Jatuphol Jaturapat |
In-app purchases
Neptune
No in-app purchases
CA'Sim
- Unlock All Features. (1 Month)1 Month trial$0.991 Month
- Unlock All Features. (3 Months)$2.993 Months
- Unlock All Features. (1 Year)$7.991 Year
- Lifetime Access$17.99









