General Average is a principle of maritime law where if a ship or its cargo is damaged or sacrificed to save the whole vessel in an emergency, the ship owner and cargo owners must proportionally share the costs of losses. This can happen if a ship encounters a major storm or runs aground, requiring some cargo to be thrown overboard to save the ship. If a ship declares General Average upon docking, each cargo owner must contribute part of the value of their cargo based on the portion sacrificed to help those whose cargo was jettisoned. Purchasing cargo insurance is advised as it can protect businesses from unexpected charges if a General Average claim is made against a ship carrying their goods.