Liquefied Gas transport by sea has originated from an idea that the gas can be liquefied and stored in tanks based on which the first LNG facilities were built in the US. First attempts to convert an oil tanker into a gas carrier were seen thereafter and was successfully carried out by a major oil company „Shell“ when they launched a converted gas carrier „Agnita“ that was equipped with independent cylindrical type od tanks that were the first tanks ever built. Further technological advancement has given us what we have nowadays, independent and membrane tanks for carriage of liquefied gases by sea. Biggest merit goes to two naval engineering companies based in France, „Gaztransport“ and „Technigas“ that have merged into a new Company called „GTT Group“ whereas they have combined their experiences and designs and produced the best possible membrane type of tank design. It is also very important to mention the importance of a Qatar national gas Compnay „Qatargas“ and their venture, a shipowner „Qatargas 2“ that has made a fleet of biggest LNG carriers in the world called Q-Max class and are fitted with membrane type of tanks. This was a move that has certainly changed the gas industry.