ARPA/ECDIS
COLLISION AVOIDANCE COLREGs-72
TIME00:00
AUTOPILOT / TELEGRAPH● GPS/GYRO
COURSE (HDG)
000°
SPEED (SPD)
15.0
ARPA MODES
VECTOR TYPE:RELATIVE
VECTOR LENGTH:6 min
ORIENTATION:
TRAILS / SWEEP:
EBL / VRM TOOLS
EBL (ELECTRONIC BEARING LINE):OFF
VRM (VARIABLE RANGE MARKER):OFF
RANGE: 12.0 NM
RINGS: 2.0 NM
MODE: R-VECT/N-UP
RINGS: 2.0 NM
MODE: R-VECT/N-UP
HDG: 000.0°
SPD: 15.0 KT
VECT: 6.0 MIN
SPD: 15.0 KT
VECT: 6.0 MIN
EBL: OFF | VRM: OFF
CPA LIM: 1.5 NM/15m
CPA LIM: 1.5 NM/15m
CURSOR: ---
⚠️ DANGEROUS APPROACH ⚠️
CPA < safety limit
Load a scenario or add a target.
COLREGs-72 EXPERTSELECT TARGET
Click a target on the radar or in the list for COLREGs-72 collision avoidance analysis.
TRIAL MANOEUVRE PARAMETERS
TRIAL COURSE:045°
TRIAL SPEED:15.0 kt
DELAY:2.0 min
☠ COLLISION
Own ship collided with T00
ARPA & Marine Radar Simulator: COLREGs-72 Collision Avoidance
The interactive ARPA (Automatic Radar Plotting Aid) online simulator is built for deck officers, nautical students, and maritime professionals preparing for competency assessments and vetting audits.
The simulator performs mathematical vector processing in real time, determining CPA (Closest Point of Approach), TCPA (Time to CPA), true aspect, range, and bearing, with integrated decision-making guidance under the COLREGs-72 framework.
Key Features & Capabilities
🎯 True vs. Relative Vectors
Switch between True Vectors (true heading and speed analysis) and Relative Vectors (instant visual identification of collision courses).
⚓ Trial Manoeuvre Engine
Simulate trial course and speed variations with configurable execution delays to verify post-action CPA clearance prior to execution.
📐 EBL & VRM Navigational Tools
Electronic Bearing Line (EBL) and Variable Range Marker (VRM) for manual bearing drift verification and radar plotting techniques.
⚖️ COLREGs Rules Diagnostics
Automated situation classification: Crossing (Rule 15 - Give-Way / Stand-On), Head-On (Rule 14), and Overtaking encounters (Rule 13).
How to Use the Simulator
- Select an Encounter Scenario: Open the «Scenarios» tab to initialize classic traffic conditions (starboard crossing, overtaking, multi-target traffic).
- Assess Collision Risk: Check the relative vectors. If a vector points directly towards your vessel's center position, a collision hazard exists.
- Review Target Data: Click any target on the display or select it from the right-hand panel to view CPA, TCPA, and applicable COLREGs obligations.
- Execute Avoidance Action: Switch to the «Trial» panel, calculate a substantial course alteration to starboard, and click «Apply Manoeuvre» to steer the vessel.
COLREGs Rule 8 Reminder: Any action taken to avoid collision shall be positive, made in ample time, and large enough to be readily apparent to another vessel observing visually or by radar. Avoid small successive course alterations.