Jettison is the deliberate act of throwing cargo or equipment overboard to save a vessel, its crew, or the remaining cargo from a greater peril — a genuine, intentional sacrifice made under emergency circumstances, distinct from cargo lost accidentally.
Why the Deliberate/Intentional Distinction Matters
For an act to qualify as jettison in the legal sense, it must be a deliberate, reasonable decision made to avert a real danger to the ship or voyage as a whole — cargo lost overboard accidentally (say, due to poor securing in heavy weather) is a loss, but not jettison in the General Average sense.
Jettison and General Average
When a genuine jettison occurs to save the ship and remaining cargo, maritime law treats it as a General Average act — the resulting financial loss is shared proportionally among all parties with a financial interest in the voyage (shipowner and all cargo owners), not borne solely by the owner of the specific goods thrown overboard. This principle reflects the idea that everyone benefited from the sacrifice, so everyone shares the cost.
Documentation Requirements
A genuine jettison event requires careful documentation — the circumstances, reasoning, and specifics of what was jettisoned — since this record becomes central to any subsequent General Average adjustment process involving surveyors, average adjusters, and all cargo interests.
Exam Relevance
Jettison and its relationship to General Average principles are standard topics in Ship Knowledge and Cargo Work sections of deck officer competency exams.