Maritime Navigation & Collision Avoidance

6 briefings

AIS Course and Speed Information

Distrust AIS course and speed data, verify independently, and assess collisions using the full bridge picture.

Open Subtopic

7 briefings

AIS Dynamic Data

AIS dynamic data works by broadcasting vessel movement details via separate position reports. Most fields update automatically from connected ship sensors, but navigational status is entered manually by the officer of the watch.

Open Subtopic

7 briefings

AIS Identity Mismatch

An AIS identity mismatch occurs when stale configured fields or invalid MMSIs create conflicting vessel names, call signs, or identifiers on a display. This discrepancy arises from data quality issues rather than deliberate deception.

Open Subtopic

7 briefings

AIS Position Reports

An unavailable AIS position report leaves no current location data, while a wrong one stems from faulty sensors because the system does not validate truth. USCG identifies Messages 1, 2 and 3 as Class A reports and Message 18 as the standard Class B report.

Open Subtopic

7 briefings

AIS Signal Loss

A missing AIS target does not prove a vessel is hidden or gone. It may result from carriage gaps, permitted switch-offs, VHF range limits, or equipment faults. A graphical display shows a lost-target symbol at the last known position when reports cease.

Open Subtopic

6 briefings

AIS Spoofing

AIS spoofing risks include misleading operational pictures; limitations stem from AIS alone proving nothing.

Open Subtopic

7 briefings

AIS Static Data

The primary limitations of AIS static data stem from its reliance on manual configuration and the absence of automatic validation. The information comprises the MMSI, call sign and name, IMO number, length and beam, ship type, and the location of the electronic position-fixing antenna.

Open Subtopic

7 briefings

AIS Transponder

Safely using an AIS transponder requires accurate inputs and a proper lookout. It never replaces radar or visual observation duties. A shipborne AIS unit automatically transmits its own data and receives data from other ships, VTS stations and other AIS stations over the AIS VHF data link.

Open Subtopic

7 briefings

AIS Vessel Identity

Operators check an AIS vessel identity by comparing its configured static fields with independent sources. The Automatic Identification System transmits a set of static identity fields that serve as claims rather than independently measured facts.

Open Subtopic

4 briefings

AIS vs Marine Radar

Radar may detect a physical target independently of AIS status because the two systems build their target pictures from different sources. AIS receives information broadcast by participating stations, while radar target information is measured by own ship's radar.

Open Subtopic

16 briefings

Automatic Identification System (AIS)

Yes, a ship can switch off its Automatic Identification System (AIS) under specific safety or security conditions. While equipment can be turned off, international guidelines require it to operate normally unless continual use compromises safety or security.

Open Subtopic

11 briefings

Automatic Radar Plotting Aid (ARPA)

Automatic Radar Plotting Aid (ARPA) connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Charted Depth

Charted Depth connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Closest Point of Approach (CPA)

Closest Point of Approach (CPA) connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Compass Cross-Check

Compass Cross-Check connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Course

Course connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Electronic Nautical Chart

Electronic Nautical Chart connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Five Short Blasts Collision Warning

Five Short Blasts Collision Warning connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Ground Speed

Ground Speed connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Gyrocompass

Gyrocompass connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Harbour Master

Harbour Master connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Heading

Heading connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

International Regulations for Preventing Collisions at Sea (COLREGs)

International Regulations for Preventing Collisions at Sea (COLREGs) connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Magnetic Compass

Magnetic Compass connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

3 briefings

Magnetic Compass vs Gyrocompass

Magnetic Compass vs Gyrocompass connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Magnetic Heading

Magnetic Heading connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

14 briefings

Marine Radar

Marine Radar connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Nautical Mile

Nautical Mile connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Navigation Beacon

Navigation Beacon connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Navigation Lights

Navigation Lights connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Paper Nautical Chart

Paper Nautical Chart connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Parallel Rulers

Parallel Rulers connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

10 briefings

Pilotage

Pilotage connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Pilot Card

Pilot Card connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Pilot Ladder

Pilot Ladder connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Position Fix

Position Fix connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Radar Bearing

Radar Bearing connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Radar Plotting

Radar Plotting connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Radar Range

Radar Range connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Radar Target

Radar Target connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Raw Radar

Raw Radar connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Sea Room

Sea Room connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Shipping Lane

Shipping Lane connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

7 briefings

Soundings

Soundings connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Speed Through the Water

Speed Through the Water connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

2 briefings

Speed Through Water vs Ground Speed

Speed Through Water vs Ground Speed connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Traffic Separation Scheme

Traffic Separation Scheme connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic

6 briefings

Under-Keel Clearance

Under-Keel Clearance connects public evidence, intelligence pressure, and fictional casework across The Collision of Tides.

Open Subtopic