Familiarisation — Free Mode
Busy-traffic familiarisation on an INTEGRATED BRIDGE display AIS targets overlaid on a radar-style PPI.
Scenario briefing
Busy-traffic familiarisation on an INTEGRATED BRIDGE display AIS targets overlaid on a radar-style PPI. This mirrors a modern ECDIS/radar where the two data sources are fused on one screen: the PPI geometry comes from radar, while vessel identity, type, COG, SOG and name come from AIS.
WHAT YOU ARE LOOKING AT
The circle and range rings are the RADAR PPI (own ship at centre, or moving across, depending on mode).
The green / yellow / red triangles are AIS symbols for each tracked vessel (radar would give blips; AIS gives identity and exact vector). The triangle points along that target's COG.
CPA/TCPA is computed from the tracked velocity vectors with an ARPA-style filter ( 25 sec), so after any course change it takes time for CPA to settle on the new value same as the real ARPA/ECDIS.
DISPLAY MODES (radar heritage)
RM (Relative Motion) your ship is PINNED to the centre of the PPI. Targets move with their RELATIVE vector (motion as seen from your deck). Channels, TSS zones and coastlines slide past you. Classic radar picture.
TM (True Motion) the world is fixed. Your ship moves across the PPI on its true ground track; target triangles follow their OWN true courses. Useful for close-quarters geometry and traffic patterns.
The RM/TM button shows the mode you will switch TO tap it to toggle.
HELM (bottom strip)
COG 10° / 1° / +1° / +10° autopilot heading setpoint (ship slews toward it at a realistic rate per vessel type).
REV / + REV engine order, ±5% of full revolutions per click (fine adjustment; hold to ramp).
DEAD SLOW commands 2 kn ahead (useful for Rule 19(e) / restricted visibility).
N engine stop (0%).
EMERG ASTERN crash-astern bell, commands 100%; once stopping, tap + REV to ease the astern bell.
The value boxes show the COMMANDED settings (autopilot heading, telegraph position). The HUD in the top-left shows the ACTUAL COG/SOG the ship has reached they lag the command because of turning inertia and engine response, exactly like real life.
PPI / SIM CONTROLS
RNG + / PPI range 3 / 6 / 12 / 24 NM.
PAUSE freezes the simulation.
×1 / ×10 / ×30 time compression.
RM / TM see above.
FULL fullscreen.
TARGET DETAIL
Click any triangle to select it. The overlay panel shows MMSI, NAME, TYPE, COG, SOG, BRG, RNG, CPA, TCPA, relative bearing and aspect the AIS payload plus derived geometry. The CPA line has a trend arrow: green = opening, red = closing, grey = steady.
📸 Bridge simulator scene
Captured directly from the SkipperCheck COLREG bridge simulator at scenario T = 0 — the moment the encounter begins.
Key teaching points
- Green / yellow / red AIS triangles point along each target's COG. Click any triangle to read MMSI, type, COG, SOG, BRG, RNG, CPA, TCPA.
- RM (Relative Motion) pins your ship at the centre and is the classic radar picture. TM (True Motion) keeps the world fixed and is better for traffic-pattern reading.
- Commanded settings (autopilot heading, telegraph) lag the ACTUAL COG/SOG shown in the HUD — exactly like a real ship with turning inertia and engine response.
- Use range steps 3 / 6 / 12 / 24 NM and time compression ×1 / ×10 / ×30 to study geometry without waiting in real time.
Common mistakes to avoid
- Reading the commanded COG and assuming the ship is already on it. Watch the HUD — that's the real heading.
- Switching to ×30 time compression in close quarters. Use ×1 or ×10 once a target is inside 6 NM.
Why it matters
Exam relevance
Bridge resource management and integrated-display familiarity are STCW Officer of the Watch baseline competencies; RYA Yachtmaster Coastal examiners expect candidates to operate radar/AIS without prompting.
Related scenarios
About SkipperCheck simulators
SkipperCheck offers two browser-based maritime training simulators:
- ARPA · AIS · COLREG Bridge Simulator — 54 scenarios covering Rules 2, 5–10, 12–19, 23–30, 34 and 35.
- VHF SRC Radio Simulator — 15 scenarios: voice Mayday, DSC distress, Mayday Relay, Pan-Pan, Sécurité, routine.
Both run in any modern browser, on desktop or mobile. No install, no plugins.