Fishing boats are used to catch and collect aquatic plants and animals. It also includes some auxiliary vessels of modern fishing production, such as those carrying out aquatic product processing, transportation, breeding, resource survey, fishery guidance and training and carrying out fishery administration tasks. In order to ensure the quality of catch, preservation is one of the important functions of fishing boats. The preservation methods on board generally include ice storage, cold seawater preservation, salt storage, micro-freezing, freezing and so on.