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Concepts

Tug Incident Classification

> ⚠️ **Manual-review required.** LLM-generated tug classifications must be checked against the source before the page is considered complete.

⚠️ Manual-review required. LLM-generated tug classifications must be checked against the source before the page is considered complete.

Why this matters

The distinction between girding and non-girding tug capsizes is safety-critical. Misclassification hides the true cause pattern and undermines the entire analytical value of this database. This is the core research focus of the Novatug project.

Decision tree

Was a tug involved in the incident?
└─ Yes → Is capsize involved?
   ├─ Yes → Was the towline/pushing forces the mechanism?
   │  ├─ Yes, explicitly described → Capsize girding
   │  ├─ No, source explicitly rules out towline → Capsize not girding
   │  └─ Unclear / not established → Capsize unknown mechanism ← DEFAULT
   └─ No → Other tug incident type (Hydrodynamic Interaction, Towhook failed to release, Collision, etc.)

Type definitions

The available information is grouped below.

Capsize girding

The tug's towline (or pushing operation) catches the vessel broadside or at the stern, creating a lateral force that pulls the tug over. The load overwhelms the tug's righting moment.

Confirm before using:

  • Source explicitly describes the girding mechanism
  • Towline angle / lead is mentioned
  • Tug was in a towing or pushing operation at the time

Capsize not girding

Tug capsizes due to weather, flooding, stability failure, or other cause clearly unrelated to towline forces.

Only use if: source explicitly states or clearly implies girding was not the mechanism. This is a high bar — don't assume.

Capsize unknown mechanism

Default classification for any tug capsize where the mechanism is not clearly established in the source material. This is not a failure — it is honest.

Hydrodynamic Interaction

The tug loses control, capsizes, or is dragged by suction or pressure wave forces from a passing or maneuvering vessel — not by its own towline.

Key indicator: a large vessel passing in close proximity is the initiating event.

Towhook failed to release

The emergency towing hook release mechanism failed under load, preventing the crew from freeing the tug. This is a equipment failure type, not a capsize type — it may combine with a capsize type.

Accidents linked to this concept are grouped by vessel type.