Ships play a vital role in promoting inter-national trade and are an indispensable factor in considering a nation's defense capabilities. Due to their valuable contribution to human life, an increase in the tonnage of vessels owned by a country is often compared to an expansion of its territory. Particularly for a country like Korea whose economy is heavily dependant on international trade, and which is surrounded by sea on three sides, ocean-going vessels provide a bridge connecting its economy with the economy of the world.