Marine casualities of tankers normally involve immeasurable risk of danger threatening the loss of human lives in the large scale of fire on the sea surface. International Convention for the Safety of Life at Sea, '83, requires oil fire test for the actual lifeboat with sprayed water in the pool on the water surface. But, the heat load from fire in the pool might be smaller than that of fire in the sea and it will be variable according to the wind velocity during test. Moreover, fire test might cause unjustifiable level of pollution and unreasonable cost of experiment. Accordingly, it has become necessary to predict the relationship between the flow rate of sprayed water on the external surface of lifeboat and the temperature of lifeboat or inboard air without conducting fire test for the actual lifeboat. This paper deals with some experiments of sprayed water, fire tests of lifeboat, and calculation of heat flow into lifeboat. The main results are summarized as follows : 1) Spectral absorption coefficient of liquid water and absorptance of sprayed water were measured to know the effectiveness of sprayed water over the external surface of lifeboat in the fire. These data are also applicable to the planning of water cooling device on embarkation deck and to the decision of flow rate on the external surface of shell to protect the explosion of tank hold surrounded by fire. 2) Four kinds of fire tests were conducted in the pool for the actual lifeboat. The measured temperatures of inside surface of boat and inboard air were in good agreement with the temperatures calculated from the simulation model of heat flow into lifeboat. 3) The alternative method to evaluate fire resistance of lifeboat was proposed without conducting fire test for actual lifeboat.