Master-Nav for iPhone

App snapshot

Master-Nav is an instructional and reference mobile app created by Peterjohn Chisholm to make learning the COLREGS (International Regulations for Preventing Collisions at Sea) straightforward and efficient. It combines interactive diagrams with a large question bank to support both learning and revision of the rules.

How the app is organized

• Practice: a hands-on area where you test your knowledge and sharpen performance through repeated questions and scenarios.
• Learning: a guided walkthrough that introduces COLREGS topics step by step and explains them in plain language.

Regulations covered

• Part D — Sound and Light Signals
• Part C — Lights and Shapes
• Part B — Steering and Sailing, Section 1
• Part A — General provisions

Standout capabilities

• Instant rule lookup via an app-wide “Rule” button that opens the exact COLREG reference related to the current question, eliminating manual searches.
• Over 900 practice questions paired with interactive visuals to reinforce understanding through realistic scenarios.
• Clear, non-technical explanations that demystify complex terminology and concepts.
• Repeated practice opportunities designed to track improvement and build retention.

Who will benefit

• New cadets and trainees preparing for maritime examinations.
• Experienced mariners seeking a quick refresher or a convenient way to review specific rules.
• Instructors looking for a compact classroom supplement or study resource.

Related recommendation

• Toca Life World — a free, creative sandbox app for building and exploring small narrative worlds (listed here as an alternative for casual exploration and interactive learning styles).