Marine Insurance Fundamentals and Ocean Marine Coverages
Marine insurance rests on a few foundational principles that exam questions probe repeatedly. Utmost good faith (uberrimae fidei) obliges the assured to disclose every material circumstance; indemnity limits recovery to the actual loss; insurable interest must exist at the time of loss (not necessarily at inception, except for life). Subrogation and contribution flow from indemnity, and the doctrine of proximate cause decides which peril triggers cover when a chain of events produces a loss.
Ocean marine traditionally splits into four branches: hull (the vessel), cargo (goods in transit), freight (earnings of the ship), and liability (protection and indemnity, collision liability). Perils are usually written on a named-perils basis (perils of the seas, fire, jettison, barratry) with Inchmaree-style additional perils covering negligence of masters and crew. Note the classic exclusions: inherent vice, ordinary leakage and wear and tear, inadequacy of packing, delay, and (for hull) ordinary deterioration.
Traps to watch: questions that conflate particular average (partial loss borne by the owner of the damaged property) with general average (voluntary sacrifice for the common safety, shared proportionally). Also watch for confusion between a warranty (breach discharges the insurer entirely under traditional English law) and a sue-and-labor clause (a duty and right to mitigate, recoverable even where the loss is otherwise excluded).
Rule of thumb: when a loss involves a sequence of causes, ask which peril set the train of events in motion without which the loss would not have occurred - that is the proximate cause. If a peril of the seas puts cargo in contact with seawater, the seawater damage is recoverable even if the seawater entered through a pre-existing weak hatch.
Worked example: A vessel grounds (peril of the seas), and the master jettisons cargo to refloat. The grounding damage to the hull is a particular average claim on the hull policy; the jettisoned cargo is a general average sacrifice, contributed to by all parties whose property was saved.