Read the water.
Right of way, decoded.
Every COLREGs rule card, the full light and shape picture, scenario drills with bearing plots and a 40-question final test. Bought once on the App Store, yours to keep — no sign-up, and your progress stays on your own device.
Head-on, narrow channel
Two power-driven vessels meeting on reciprocal courses. Decide the safe, lawful response.
Each vessel alters to starboard and sounds one short blast — pass port-to-port.
Reducing speed alone in a head-on meeting — it only delays the encounter.
Core rule cards
The clauses that decide most encounters at sea.
Head-on situation
When two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision, each shall alter her course to starboard so that each shall pass on the port side of the other.
Crossing situation
When two power-driven vessels are crossing so as to involve risk of collision, the vessel which has the other on her own starboard side shall keep out of the way and shall, if the circumstances admit, avoid crossing ahead of the other vessel.
Responsibilities between vessels
The pecking order: a power-driven vessel keeps clear of vessels not under command, restricted in ability to manoeuvre, engaged in fishing, and sailing vessels. A sailing vessel keeps clear of fishing vessels, RAM and NUC. A fishing vessel keeps clear of RAM and NUC.
The safe-speed checklist
Rule 6 distilled into the checks an examiner expects you to name.
Study Rule 6 →Adequate speed to stop inside the range of visibility.
Steering and manoeuvring ability preserved, not just speed.
Background shore lights and the limits of your radar.
Traffic density, sea state, and your draught versus depth.
Buy it once. Keep it.
One payment on the App Store unlocks HelmChart in full — every rule card, light picture, drill and the final test. No subscription, no renewals, no locked extras later.
Pay once through the App Store. Nothing recurring, and nothing else to buy inside.
No sign-up, no email, no password. Your purchase is tied to your Apple ID.
Answers and scores are saved on your device only, and you can clear them any time.
HelmChart is a study aid for the International Regulations for Preventing Collisions at Sea. It is not a navigation instrument and must not be used for decisions at sea — always verify against the official IMO text and your own vessel's procedures.