# Navigation Rules vs Shellback

The clearest difference is price: Shellback at Free against Navigation Rules's $3.99. Navigation Rules's advantage is rating (4.8 vs 3.2) and review sentiment (86% vs 45%). On ads, in-app purchases, monetization model and device support there is nothing between them.

Shellback is free to download; Navigation Rules costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Navigation Rules holds the better App Store score, 4.8 against 3.2. That said, the two scores are not equally well evidenced: Navigation Rules has 386 ratings behind it against 38, so its average is the more settled of the two. Written reviews point the same way: 86% of Navigation Rules's written reviews are positive against 45% of Shellback's.

Navigation Rules ships an update every 4 months, Shellback every 10 months. The most recent releases landed on September 26, 2026 and June 9, 2026 respectively.

## The numbers

| Metric | Navigation Rules | Shellback |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[4.8 (386 ratings)](https://appshunter.io/ios/app/navigation-rules/id327936562/reviews)** | [3.2 (38 ratings)](https://appshunter.io/ios/app/shellback/id955157952/reviews) |
| Number of ratings | **386** | 38 |
| Positive reviews | **85.7% of reviews** | 45.2% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 months** | Every 10 months |
| Monetization | Free | Free |
| Best chart rank | **#138** | — |
| Size | 35 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

[App page](https://appshunter.io/ios/app/navigation-rules/id327936562)

**Currently charting:** #138 Top Paid · Reference (US App Store)

Access the complete International Regulations for Preventing Collisions at Sea (COLREGs) and Inland Navigation Rules. This app provides a searchable, annotated version of boating regulations, ideal for quick reference and sharing information.

**Highlights:** COLREGs and Inland Navigation Rules, Annotated table of contents, Search function, Favorites page, Email sharing

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

**In-app purchases:** none

**What reviewers like**

- 👍 Easy to navigate and user-friendly interface
- 📚 Comprehensive reference material for navigation rules
- 🚀 Quick access to rules on-the-go
- 🎓 Excellent study tool for maritime exams and licenses
- 📖 Well-organized table of contents and structure

**What reviewers complain about**

- 🐛 Poor navigation between rules requires multiple menu presses
- 📄 Walls of text with limited visual content
- 🎨 Inconsistent formatting in some sections (e.g., 8F(iii))
- ❌ Limited additional features beyond basic text content
- 🔄 Clicking definitions forces users to search for original page again

**Reported bugs**

- Formatting inconsistency in rule 8F(iii)
- Navigation issues when jumping between non-sequential rules
- Definition links don't provide easy return to original page
- Typos present in content

**Requested features**

- Quiz or test functionality for self-assessment
- Easier rule-to-rule navigation without menu cycling
- More visual illustrations and diagrams throughout
- Back button functionality when accessing definitions
- Option to separate international and inland rules


### 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 free?

Navigation Rules costs $3.99, with no in-app purchases.

### Is Shellback free?

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

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

Navigation Rules is rated higher. Navigation Rules averages 4.8 out of 5 from 386 ratings, while Shellback averages 3.2 from 38 ratings.

### Do Navigation Rules or Shellback have ads?

Neither Navigation Rules nor Shellback shows ads.

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

Navigation Rules ships an update every 4 months, and Shellback every 10 months. Most recently, Navigation Rules was updated on September 26, 2026 and Shellback on June 9, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*