Q-Max

Q-Max is a type of ship, specifically a membrane type liquefied natural gas carrier. In the name Q-Max, "Q" stands for Qatar and "Max" for the maximum size of ship able to dock at the LNG terminals in Qatar. Ships of this type are the largest LNG carriers in the world.
Technical description.
A ship of Q-Max size is long and measures wide and high, with a draft of approximately .
It has an LNG capacity of , equal to of natural gas. It is propelled by two slow speed diesel engines burning HFO, which are claimed to be more efficient and environmentally friendly than traditional steam turbines. In case of engine failure, the failed engine can be de-coupled allowing the ship to maintain a speed of 14 knots.
Q-Max vessels are equipped with an on-board re-liquefaction system to handle the boil-off gas, liquefy it and return the LNG to the cargo tanks. The on-board re-liquefaction system allows a reduction of LNG losses, which produces economic and environmental benefits.
Overall, it is estimated that Q-Max carriers have about 40% lower energy requirements and carbon emissions than conventional LNG carriers. The quoted estimates do however ignore the additional fuel used to re-liquify boil off gas rather than burn the gas for fuel. The ships run on Heavy fuel oil (HFO), but the Rasheeda was retrofitted with gas-burning ability in 2015.
Contractors.
Q-Max LNG carriers were ordered in 2005. They are built by Samsung Heavy Industries and Daewoo Shipbuilding & Marine Engineering. The installed Boil Off Gas re-liquefaction system (Ecorel) is developed and delivered by Cryostar, and approved and certified by Lloyds Register.
Ships.
The first Q-Max LNG carrier was floated out of dry-dock in November 2007. The naming ceremony was held on 11 July 2008 at Samsung Heavy Industries' shipyard on Geoje Island, South Korea. Known before its naming ceremony as Hull 1675, the ship was named "Mozah" by Sheikha Mozah Nasser al-Misnad. "Mozah" was delivered on 29 September 2008. It is classed by Lloyd's Register. The first trip by a Q-Max tanker was completed by "Mozah" itself on 11 January 2009, when the tanker delivered 266,000 cubic metres of LNG to the Port of Bilbao BBG Terminal. Days before, the vessel had transited the Suez Canal for the first time.
Q-Max LNG carriers are operated by the STASCo (Shell International Trading and Shipping Company, London part of Shell International. They are owned by Qatar Gas Transport Company (Nakilat) and they are chartered to Qatar's LNG producers Qatargas and RasGas. In total, contracts were signed for the construction of 14 Q-Max vessels.
Fourteen sister vessels are in service named: Mozah, Al Mayeda, Mekaines, Al Mafyar, Umm Slal, Bu Samra, Al Ghuwairiya, Lijmiliya, Al Samriya, Al Dafna, Shagra, Zarga, Aamira, and Rasheeda. All 14 Q-Max ships were delivered in 2008 through 2010.