# Shellback

> Offline reference app for US Naval Surface Force personnel. (iPhone/iPad app by Program Executive Office for Enterprise Information Systems, Sea Warrior Program.)

- Source: https://appshunter.io/ios/app/shellback/id955157952 (this page in markdown: same URL + `.md`)
- Developer: [Program Executive Office for Enterprise Information Systems, Sea Warrior Program](https://appshunter.io/developer/1477503418)
- Category: Reference, Education
- Price: Free
- Rating: 3.20/5 from 38 App Store ratings · 42 written reviews indexed
- Age rating: 12+
- Requires: iOS 15.0 · 71 MB
- Released: 2015-03-11
- Data updated: 2026-06-09
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/shellback/id955157952/reviews.md

## What is Shellback?

What is the Shellback app? 
Shellback, formerly known as eDivo, is a free mobile app developed to support US Naval Surface Force (SURFOR) personnel in an easy-to-access offline environment.  

What is a Shellback? 
In naval tradition, a Shellback is a nickname for a Sailor who has crossed the Equator and thus transitioned from a novice Sailor, or Pollywog, to an experienced Sailor.

Why do I need Shellback?
Shellback provides Sailors the ability to download key SURFOR information on their own portable devices and access it while underway without the need for an internet connection.  Shellback provides the most relevant and current information to SURFOR Sailors in one location. Content is scheduled for annual updates. 

What type of info can I find in Shellback? 

The information in Shellback is separated into several main categories: 
-Admin/Training: Contains the Correspondence Manual and the SURFOR Training and Readiness Manual.
-Medical: Includes the Manual of the Medical Department, information on medical and physical readiness, mental health, Medical Evaluation Board procedures, the Disability Evaluation System, family member readiness, and more.
-Operations: Includes information and training on bridge management, navigation basics, watch team tools, crew endurance, operating procedures for air-capable ships, Air Certification for Naval Surface Force Ships, and manuals for amphibs, maintenance, and other general ship operation resources.
-Personnel Management: Provides documents on Navy personnel policy and administration. Also includes legal handbooks and manuals, resources for Surface Warfare Officers, and a variety of general personnel management resources. 
-Safety: Provides documents related to lessons learned, mishap reporting, notices, safety-related awards, and general safety resources.
-Rules of the Road: This quiz tests a Sailor’s knowledge of maritime navigation rules.

## Key features

- 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

## Recent user reviews (10 of 42)

All indexed reviews: https://appshunter.io/ios/app/shellback/id955157952/reviews.md

### 1/5 — Not so great

*2025-04-26, version 2.2*

This app is out of date!  Why does the navy not put the time in to the products to ensure members have the most recent instructions?  Also,  why not add more things to this app?

### 1/5 — Poor maintenance of instructions and references

*2024-10-10, version 2.2*

Updates to the references and instructions are not the latest. Do better.

### 1/5 — Not useful for ROR practice

*2023-05-11, version 2.1*

The ROR practice quiz should be a great feature. However, if you get a question wrong there is zero explanation/indication of what the correct answer is…and therefore zero opportunity to learn. Disappointingly limited.

### 4/5 — Love this app!

*2022-11-17, version 2.1*

I love this app I just wish you could be told what the correct answer is on the ROR quiz after you answer the wrong one.

### 2/5 — Rules of the Road and Feedback need improvement

*2022-09-15, version 2.0*

The Rules of the Road quiz portion is a valuable tool to work on skills, but should be updated to show what the correct answer should have been when you get one wrong. On the iPhone 13pro, the app crashes when I try to put my name in the feedback bar, preventing me from actually giving this feedback as actual feedback.

### 3/5 — RoR feature

*2022-08-26, version 2.0*

The RoR feature is a good way to practice, however I wished it would provide feedback with the right answer and maybe even show the rule related to the question from the COLREGs

### 1/5 — Rules of the Road

*2022-08-10, version 2.0*

The Rules of the Road quiz needs to provide correct answers to be effective. Highly disappointing this feature no longer exists.

### 1/5 — Do not use for Rules of the Road

*2022-07-06, version 2.0*

This last update stopped showing you the correct answer on Rules of the Road quizzes. It just turns red and does nothing else. You can now go F yourself is the business model the developers switched over to. This used to be, hands down, the best app to take quizzes on because it showed you immediately the correct answer if you got it wrong. F** it. Let ships collide.

### 5/5 — Please display the correct answer on the ROR quiz

*2022-06-20, version 2.0*

The ROR quiz no longer displaces the correct answer on the question if you get it wrong and that’s a bit frustrating.

### 1/5 — QUATERMASTER SCPO

*2022-05-26, version 2.0*

Adding more check list instructions is helpful, but removing all RATING MANUALS, and Bridge watch team training tools is not helpful.

## Frequently asked questions about Shellback

### What is the Shellback app?

Shellback is a free mobile application designed to support US Naval Surface Force (SURFOR) personnel by providing easy-to-access offline information. It was formerly known as eDivo.

### What kind of information is available in the Shellback app?

The app contains information categorized into Admin/Training, Medical, Operations, Personnel Management, Safety, and Rules of the Road. This includes various manuals, readiness resources, operating procedures, policy documents, and safety lessons learned.

### Is the Shellback app free to use?

Yes, the Shellback app is completely free to use. It does not have any in-app purchases or advertisements.

### Can I use the Shellback app without an internet connection?

Yes, a primary feature of the Shellback app is its ability to provide offline access to key SURFOR information. This allows Sailors to access necessary resources while underway, even without an internet connection.

### How often is the information in the Shellback app updated?

The content within the Shellback app is scheduled for annual updates. This ensures that SURFOR Sailors have access to the most relevant and current information available.

## Version history (last 5 releases)

### 2.3 — 2025-10-31

-- Bug fixes and stability updates

### 2.2 — 2024-08-30

-- Bug fixes and stability updates

### 2.1 — 2022-10-19

-- Bug fixes

### 2.0 — 2022-05-20

-- Five new sections: Admin/Training, Medical, Operations, Safety, and Ship Operations 
-- Updated content, instructions, and PDFs
-- Rules of the Road quiz and much more!

### 1.7.11 — 2017-04-21

This app has been updated by Apple to display the Apple Watch app icon.

- Content updates and bug fixes

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-09.*