With most of oil tankers, the steam is used to run a pump attached to turbine when the cargo oil is being loaded. The vacuum condenser is installed to generate back-pressure for improving turbine performance, and recollecting exhaust steam. Additionally, it can be used to recollect steam that discharged from tanker ship with inert gas system. Generally, the high efficiency ejector or vacuum pump unit is attached to vacuum condenser in order to eject non-condensable gas.