A vessel casualty that does not qualify as a very serious casualty and involves a fire, explosion, grounding, contact, heavy weather damage, ice damage, hull cracking or suspected hull defect, etc., resulting in:
- Structural damage rendering the vessel not navigable, such as penetration of the hull underwater, immobilization of main engines, extensive accommodation damage, etc.; and/or
- Pollution (regardless of quantity); and/or
- Breakdown necessitating towage or assistance from the shore.