# Navigation Rules Pro vs Shellback

The clearest difference is price: Shellback at Free against Navigation Rules Pro's $4.99. Navigation Rules Pro's advantage is rating (4.8 vs 3.2) and review sentiment (85% vs 45%). On ads, in-app purchases and device support there is nothing between them.

Shellback is free to download; Navigation Rules Pro costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Navigation Rules Pro holds the better App Store score, 4.8 against 3.2. That said, the two scores are not equally well evidenced: Navigation Rules Pro has 442 ratings behind it against 38, so its average is the more settled of the two. Written reviews point the same way: 85% of Navigation Rules Pro's written reviews are positive against 45% of Shellback's.

Navigation Rules Pro ships an update every 3 months, Shellback every 10 months. The most recent releases landed on September 24, 2026 and June 9, 2026 respectively.

## The numbers

| Metric | Navigation Rules Pro | Shellback |
| --- | --- | --- |
| Price | $4.99 | **Free** |
| Rating | **[4.8 (442 ratings)](https://appshunter.io/ios/app/navigation-rules-pro/id494309072/reviews)** | [3.2 (38 ratings)](https://appshunter.io/ios/app/shellback/id955157952/reviews) |
| Number of ratings | **442** | 38 |
| Positive reviews | **85.0% of reviews** | 45.2% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 10 months |
| Monetization | Paid | **Free** |
| Best chart rank | **#37** | — |
| Size | 37 MB | 71 MB |
| Requires iOS | **9.3** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 12+ |
| Developer | [Calculated Industries](https://appshunter.io/developer/370406449) | [Program Executive Office for Enterprise Information Systems, Sea Warrior Program](https://appshunter.io/developer/1477503418) |

## What reviewers say

### Navigation Rules Pro

[App page](https://appshunter.io/ios/app/navigation-rules-pro/id494309072)

**Currently charting:** #37 Top Paid · Reference (US App Store)

This app provides comprehensive boating regulations and reference materials, including international and inland navigation rules, sound and light signals, and communication information. It features quick references, calculators, and unit conversions for boaters.

**Highlights:** International and Inland Navigation Rules, Sound and Light Signals Quick Reference, Aids to Navigation (AtoN), Communication Information (DSC, Morse Code, etc.), Boating Calculators, Unit Conversions, Search and Favorites functionality

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

**In-app purchases:** none


### Shellback

[App page](https://appshunter.io/ios/app/shellback/id955157952)

This app provides US Naval Surface Force personnel with offline access to essential information. It includes manuals and resources for administration, medical, operations, personnel management, safety, and navigation rules. Content is updated annually for relevance.

**Highlights:** Offline access to SURFOR information, Admin/Training manuals, Medical readiness resources, Operations and navigation training, Personnel management documents, Safety information and lessons learned, Rules of the Road quiz

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Navigation Rules Pro free?

Navigation Rules Pro costs $4.99, with no in-app purchases.

### Is Shellback free?

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

### Which has better reviews, Navigation Rules Pro or Shellback?

Navigation Rules Pro is rated higher. Navigation Rules Pro averages 4.8 out of 5 from 442 ratings, while Shellback averages 3.2 from 38 ratings.

### Do Navigation Rules Pro or Shellback have ads?

Neither Navigation Rules Pro nor Shellback shows ads.

### Which is updated more often, Navigation Rules Pro or Shellback?

Navigation Rules Pro ships an update every 3 months, and Shellback every 10 months. Most recently, Navigation Rules Pro was updated on September 24, 2026 and Shellback on June 9, 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.*