Case study
6 Milles, a revision app designed like a ship’s instrument
An iOS and Android app we design, build and publish ourselves: revise for the French coastal boating licence, then keep the app on board once the licence is in hand.
The project
The coastal licence is the theory test of France’s sea boating licence, also required to ride a jet ski. Revising often means working through series of multiple-choice questions without knowing what has really been learned. We wanted an app that does the opposite: spot weak points, work on them until they are mastered, and prepare for the exact format of the test.
And once the licence is earned, the app shouldn’t end up forgotten in a folder: it becomes a tool on board. Hence its name — six nautical miles from shelter is how far the coastal licence lets you sail.
1,000+
questions covering the whole coastal licence syllabus
100+
illustrated questions: lights, flags, buoyage, charts
40
questions per mock exam, in the official format
What we built
Revise better, not more
Every screen serves one idea: know what is learned, work on what isn’t, and reach the exam with no surprises.
Revision that adapts to each learner
Every question has its own mastery level. A mistake is explained, then the question comes back until it is learned; “Review my mistakes” works on weak points only. Given their exam date, learners get a daily goal and, if they wish, a daily reminder.
Illustrations just like on exam day
Night lights, international code flags, crossing situations seen from above, chart extracts: over a hundred illustrated questions, all drawn by the app itself, sharp on every screen, in light and dark mode. A game, “Night watch”, trains learners to identify lights and then manoeuvre by the steering rules.
Mock exams in the official format
40 questions, one or two correct answers each, 5 mistakes at most, and an optional 20-second timer like on the exam tablet. Every answer cites the rule that applies (COLREGs, French safety regulations, IALA buoyage), with a link to report an error.
An app that stays on board after the licence
Study notes for each topic, illustrated cards for every buoyage mark, then tools for the water: a Mayday call ready to read on the VHF with the GPS position, man overboard, a bearing compass, speed and heel, tide calculations and the mandatory equipment for each zone.
The choices
An app that is simple to install, and respectful
One codebase for iOS and Android
React Native and Expo: a single codebase published on both stores, with content fixes shipped without waiting for a new release.
No account, no ads
Progress stays on the phone. The GPS position is only used by the tools that need it and never leaves the device. Reminders are local notifications, with no server.
Free to try, then a one-off purchase
A selection of questions from each topic, a mock exam, My Mayday and Man overboard are free; the full version unlocks with a single payment, no subscription.
A store listing worked like a web page
Name, subtitle, keywords and screenshot captions are chosen from what learners actually search for, just as we would for a website’s SEO.
Where the project stands
The app is ready and its release on the App Store and Google Play is coming soon. The first figures — downloads, the searches that lead to the listing — will be added to this case study.
An app project in mind?
From the idea to the store listing, we design useful, understated apps that are easy to pick up. Let’s talk about yours.
