The perils of the sea is relatively the most important part of marine insurance. The concept of insured perils signifies a very central issue under maritime insurance where the assured`s property or profit are put at risk by maritime perils and the insurer agrees to indemnify the assured against any loss caused by those perils. In practice, the extent of the covered risks is determined by the agreement of the parties by selecting the appropriate set of Institute Clauses. It is a general principle that the assured claiming for a loss should discharge the burden of proving that the loss of the claim was caused by a peril insured against under the policy. However, the assured often face a difficulty in carrying this burden of proof when the vessel sank in unexplained circumstances. As for the degree of proof, the plaintiff has to prove on a balance of probabilities that the ship was lost by a perils of the seas. Therefore, in voyage policy, the presumption of the unseaworthiness can be overturned if it is proved that the ship was seaworthy at the commencement of the voyage. However, in time policy, it would be insufficient to prove that a ship was seaworthy just before the loss. When, with the privity of the assured, the ship is sent to sea in an unseaworthiness state, the insurer is not liable for any loss attributable to unseaworthiness.