DatumMark is an IALA Maritime Buoyage System reference and exam revision app. It covers all lateral, cardinal, isolated danger, safe water, special, and emergency wreck marks for both IALA Region A and Region B. All data is bundled — no internet connection required.
Browse all sea marks organised by category. Each mark shows an accurate colour swatch, full colour description, topmark details, and light characteristics. Tap any mark to view a rendered buoy with hull colours, topmark, and light rhythm animation.
Quick Reference Card showing all marks at a glance. Light rhythm reference with descriptions and example marks. Buoy shape and topmark shape glossaries.
Full-text search across mark names, colour descriptions, light characteristics, and group names. Results update as you type.
RYA-style exam practice. Identify marks from rendered buoy images in sessions of 10 questions. Pass mark is 7/10. Three modes: identify by name, identify by light character, and identify by colour description. Questions respect your IALA Region selection.
Choose between amber, green, or red display themes. Red preserves scotopic (night-adapted) vision — recommended for bridge use during hours of darkness. Select IALA Region A or B. Your preferences are saved between sessions.
For support queries, please open an issue on GitHub.