Appworthy
App Store
Version 1.50 · 2026-06-15
New improved artwork and content, minor bug fixes.
App Store rating4.8★100 ratings
Price$1.99Listed price
Age4+Store age rating
Size123 MBiPhone download
CategoryEducation
DeveloperPeterjohn Chisholm
What we found
Full reportToo little checked to say Store information only. We haven’t analysed this app or read its reviews yet.
Money
- $1.99 to download.
Not yet tested.
The store currently lists version 1.50, updated 2026-06-15.
Preview
Store screenshots supplied by the developer.
About this app
Master-Nav is a progressive COLREGS learning system developed by a Master Mariner. The COLREGS are notoriously difficult to learn and retain — Master-Nav makes it significantly easier through an interactive system built around how your brain actually works.
Instead of guessing through random question banks, Master-Nav guides you step by step through every rule from start to finish. Wrong answers are revisited until the rules stick — properly.
Complex regulations are broken down into learnable chunks — bite-sized sections supported by mnemonics, memory aids and interactive visuals designed around how the brain actually retains information.
Every incorrect answer is shown graphically alongside the correct one — immediately clear, no confusion. And with a single tap, the relevant COLREGS rule is accessible from any question at any time.…
From the developer’s store description.
For developers and the curious
The full report
The evidence, sources, measurements and versions behind every label above.
Findings and evidence
Not yet tested. No analysis has been published for this app. A missing label is not a clean bill of health.
What reviewers report
No review analysis published for this app.
Measurements
“Not assessed” means we could not measure it. It is never a zero and never a pass.
From store data and reviews
Developer replies to reviews
Not assessed
Fewer than 50 reviews scanned — too few to state a rate
Price in the store description
The store description doesn’t list prices (most don’t)
Cancelling, in the store description
The store description doesn’t say how to cancel (most don’t)
Themes reported by reviewers
Not assessed
This app's reviews have not been assessed yet
Five-star share of ratings
80–89% five-star
Arithmetic on the stores' own published rating counts. It says nothing about why the ratings fall where they do.
In the app package we scanned
No package has been scanned for this app, so nothing is published about what it ships. That is an absence of evidence, not a finding.
Sensitive permissions
Not assessed
No package has been scanned for this app
Analytics or tracking SDKs in the scanned package
Not assessed
No package has been scanned for this app
Advertising SDKs in the scanned package
Not assessed
No package has been scanned for this app
How we know
Supporting measurements: not a complete list of possible harms or positives. Measurement vocabulary 1.4 · how these are measured
Versions and dates analysed
Not yet tested. No analysis has been run for this app, so there is no version or date to report.
Store update history
Each store’s release notes, as the developer wrote them. They are the developer’s words, not ours.
Assessment record
- Status
- Not yet tested
- App identifier
master-nav- Sources used
- None recorded
- Reviews read
- None recorded
- Package examined
- No package scan
- Human inspection
- Not completed
How we know
- Measurement vocabulary
- 1.4
Store facts
What the stores publish. Store ratings are the stores’ numbers, not Appworthy’s, and are never averaged across stores.
App Store
- Store rating
- 4.75 ★ · 100 ratings
- Version
- 1.50
- Updated
- 15 Jun 2026
- Price
- $1.99
- Age rating
- 4+
- Size
- 123 MB
- Developer
- Peterjohn Chisholm
- Category
- Education
- Listing price
- $1.99
No itemized purchase list is available for this listing.
Method and limits
What a missing label means
Not yet tested. No analysis has been published for this app, so there is no method to describe for it yet. A missing label is not a clean bill of health: it means nothing has been read, not that nothing is wrong.
Limits of this report
- A package scan is static. It identifies code and text in one Android build. It does not measure a live ad session, test a deletion request, or count the steps needed to cancel.
- Reviews keep their sample. A review-only charge shows distinct reviewers, the share and the sample size, and is published only once it clears that label’s published threshold. Calibration labels are machine-drafted and not yet confirmed by a person.
- Not assessed is a state. It is never a zero and never a pass.
- A missing label is not a clean bill of health. It means the evidence did not support one, not that the app is problem-free.
Not yet human-reviewed. A human review gives an app hands-on, recorded measurements. None has been run for this app. Hands-on inspections are not yet open.
Request a correction
Write to [email protected], or use the form. Name the finding, the app version and the evidence that needs correcting. Factual corrections are free and never depend on buying anything.