Comparison

Neptune vs Electric Field Explorer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • 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
Features
Read full description

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.

About

Electric Field Explorer

Features
Read full description

E-Field Explorer makes electric fields visible and intuitive. Place positive and negative charges directly on the field, move them freely, and watch field lines, equipotential lines, and field strength update in real time. Use preset scenes such as a single charge, dipole, quadrupole, capacitor, or hollow sphere for a quick start, then adapt each setup to your own experiment. You can adjust charge strength for selected charges and optionally show labels for clearer orientation. The integrated particle emitter makes field behavior especially easy to grasp. Choose positive or negative test charges, automatic emission or single pulses, and damped or undamped motion. That makes the app ideal for teaching, self-study, and visual demonstrations on iPhone and iPad. Features: - Place positive and negative charges with drag and drop - Toggle field lines, equipotential lines, and heatmap - Adjust the strength of individual charges - Start from preset scenes for common electrostatic setups - Share screenshots directly from the app

Screenshots

Neptune4 screens
Electric Field Explorer4 screens

Verdict

The call

The clearest difference is price: Neptune at Free against Electric Field Explorer's $1.99. Neptune also leads on update cadence (every 4 days vs every 2 months) and iOS requirement (15.0 vs 26.0). On ads, 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

CostPrice · In-app purchases · Ads · Monetization

Neptune is free to download; Electric Field Explorer costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Neptune ships an update every 4 days, Electric Field Explorer every 2 months. The most recent releases landed on October 25, 2026 and October 6, 2026 respectively.

Scorecard3 real differences · 7 level
Neptune versus Electric Field Explorer: the parameters behind the verdict, then further details
ParameterNeptuneElectric Field Explorer
PriceFree — better$1.99
Rating5.0 (17 ratings) — better—
Positive reviews100.0% of reviews—
Number of ratings17 — better—
Update frequencyEvery 4 days — betterEvery 2 months
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better26.0
Further details — not scored
Size96 MB4 MB
Age rating4+4+
DeveloperBrice BrownHolger Wiesing

In-app purchases

None

Neptune

No in-app purchases

None

Electric Field Explorer

No in-app purchases

Questions

Is Neptune free?
Neptune is free to download, with no in-app purchases.
Is Electric Field Explorer free?
Electric Field Explorer costs $1.99, with no in-app purchases.
Do Neptune or Electric Field Explorer have ads?
Neither Neptune nor Electric Field Explorer shows ads.
Which is updated more often, Neptune or Electric Field Explorer?
Neptune ships an update every 4 days, and Electric Field Explorer every 2 months. Most recently, Neptune was updated on October 25, 2026 and Electric Field Explorer on October 6, 2026.

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