Concepts | Novatug Maritime Wiki

Concepts

Definitions and explanations of towing, vessel handling, bollard pull, escort operations, and port procedures.

Allision

Allision is contact between a moving vessel and a fixed structure, moored vessel, or anchored vessel.

Anchor Watch

An anchor watch is the continuous monitoring of a vessel's position, environmental conditions, and readiness while at anchor.

Azimuth propulsion

Azimuth propulsion uses propulsors that can rotate to direct thrust through a wide arc rather than relying on a fixed shaft and rudder arrangement.

Bow-wave effect

Bow-wave effect is the pressure field and water displacement generated near the bow of a moving vessel that can push or destabilize a smaller nearby craft.

This retrieval concept groups cases where a vessel breaks free from its berth, moorings, or restraint arrangement and begins drifting or moving without intended control. It is broader than any single controlled `incident_type` because the breakaway may escalate into a terminal accident, allision, collision, or grounding.

Bridge Resource Management Failure

**Definition:** Systematic breakdown in the coordination, communication, and decision-making processes among bridge watchstanders during navigation, resulting in avoidable collisions or near-misses.

Bridge Resource Management

Bridge resource management is the coordination, communication, and workload-sharing discipline used to navigate safely on the bridge.

Capsize Girding

A tug capsize caused by the towline pulling the tug broadside or stern-to the direction of load, overwhelming its righting moment. The tug is "girded" — caught by its own towline and unable to recover.

Capsize Not Girding

A tug capsize caused by factors other than towline forces — typically weather, flooding, stability failure, or structural failure.

Capsize Unknown Mechanism

This page is the exact browse hub for accident pages classified as `Capsize unknown mechanism`.

Cargo Loss

This page is the exact browse hub for accident pages classified as `Cargo Loss`.

Cell Phone Distraction (Maritime)

This concept covers navigation and watchkeeping cases where personal-device distraction degraded attention, monitoring, or response.

Collision vs Allision

| Term | Definition | |---|---| | **Collision** | Both vessels were **moving** at the time of impact | | **Allision** | One vessel was **moving**; the other was stationary (moored, anchored, or a fixed structure) |

Collision Watchkeeping Failure

This concept covers collision cases where watchkeeping, contact monitoring, or alerting broke down before impact.

Collision

Collision is contact between two moving vessels.

Departure stability and cargo distribution failure

This concept page covers casualties where the vessel's departure condition was unsafe because the stability margin, ballast condition, or cargo distribution was inadequate before sailing.

Downflooding

Downflooding is the progressive entry of water into a vessel through openings that are not intended to remain watertight once the vessel heels, trims, or loses freeboard.

Dynamic Load in Towing

Dynamic load in towing is the transient increase in towline force caused by vessel motion, wave action, shock loading, or abrupt changes in relative speed and direction.

ECDIS route planning and alarm management failure

This concept page covers groundings where the vessel's ECDIS was central to navigation, but poor route planning, unsafe configuration, weak checking, or misunderstood alarms allowed an unsafe route or unsafe proximity to hazards to go unrecognized.

Electronic chart system grounding-avoidance configuration

This concept page covers cases where a charted grounding hazard existed in the navigation system, but display settings, user configuration, or operator understanding prevented the hazard from being recognized in time.

Engine Failure

This page is the exact browse hub for accident pages classified as `Engine Failure`.

EPIRB

EPIRB stands for Emergency Position-Indicating Radio Beacon. It is a distress beacon intended to alert rescue authorities after a vessel casualty and, when properly configured, provide a location signal.

Explosion

Explosion covers casualties in which blast, deflagration, or rapid pressure release was a primary part of the event or its escalation.

Fatigue and Alertness

Fatigue and reduced alertness are human-performance conditions that can degrade lookout, monitoring, decision-making, communication, and response during navigation or emergency work.

Fire / Explosion

This page is the exact browse hub for accident pages classified as `Fire / Explosion`.

Fire / Sinking

This page is the exact browse hub for accident pages classified as `Fire / Sinking`.

Fire

This page is the exact browse hub for accident pages classified as `Fire`.

Free surface effect

Free surface effect is the reduction in stability caused by liquid moving across a partially filled tank or flooded space.

Girding

Girding is the dangerous condition in which a tug is pulled sideways or stern-first by towline force and loses the ability to recover its heading. If the heel increases far enough, the tug may capsize.

Gog and Gob Rope / Bridle Wire

Gog ropes, gob ropes, bridle wires, and related chains are towing-control arrangements used to manage the lead, geometry, and lateral movement of a towline. The terms are related but not interchangeable, so the accident page preserves the wording used by each source.