Most of fishing vessels pour plain ice into fish storages to maintain freshness of catches, which causes varying storage temperatures and changes in the salinity, and damages in catches. In contrast, seawater cooling systems that directly chill the seawater in the storage provide seawater with a constant temperature and salinity. Furthermore, the application of a flood-type evaporator enables the size of the system to be reduced due to the enhanced heat transfer performance of the evaporator. This study conducts experimental research on the boiling heat transfer characteristics of flood-type evaporators under various operating conditions. The test section of the experiment consists of the flood-type evaporator including tubes made of three different materials and having two different shapes, and R134a and R22 are used. As a result, low-fin tubes were found to present a higher heat transfer coefficient than that of the plain tube. Aluminum-brass low-fin tubes exhibited relatively 4.5% higher heat transfer coefficient than that of copper-nickel low-fin tubes when R22 was used, and relatively 5.3% higher value when the R134a was used. When R22 was used with an aluminum-brass low-fin tube, the heat transfer coefficient was relatively 6.9% higher than that when using R134a.