Modern dual fuel engine is looking for a new alternative fuel because of the higher prices and lower production of diesel. Jatropha biodiesel is a promising substitute as an alternative fuel has gained significant attention due to the predicted shortness of conventional fuel and environmental concerns. The operating test values obtained from the Jatropha oil is closely matched with the values of conventional diesel and can be used in the existing diesel engine without any modification. This paper studies the most promising propulsion alternatives of future Liquefied Natural Gas (LNG) carriers running by dual fuel engine used boil off natural gas (BOG) from LNG carriers cargo tanks vessels as main fuel and Jatropha biodiesel oil as pilot fuel. An experimental investigation was performed to investigate the influence of dual-fuel combustion on the performance and exhaust emissions of a direct injection (DI) diesel engine fueled with Jatropha oil and natural gas (NG). A single cylinder diesel engine was set up and arranged to measure and study the engine performance at all running parameters. The test rig aims to simulate the operating conditions of BOG in propulsion machinery of LNG carriers. The present investigation studies the engine performance and emissions experimentally at different loads to obtain the best load condition by using natural gas and Jatropha biodiesel oil. The obtained results showed that the thermal and volumetric efficiency of diesel engine is higher than Jatropha biodiesel engine. The specific fuel consumption, exhaust gas temperature, HC, CO2 and NO were comparatively higher in Jatropha biodiesel. While an appreciable increase in cylinder pressure and CO emission when using diesel. It was observed that the combustion characteristics of the Jatropha biodiesel followed closely with that of the base line diesel. This means that, Jatropha biodiesel can be used instead of diesel fuel oil with safe engine operation.