Semi-submersible Heavy Transport Vessels are vital to the shipping industry. They are employed in several offshore roles, such as transporting offshore drilling rigs, FPSOs, oil production platforms, foundations for offshore wind farms and other heavy cargo. Read further to learn about the 12 Biggest Semi-Submersible Heavy Transport Vessels, listed according to their carrying capacity. 1. Boka Vanguard Earlier known as Dockwise Vanguard, this semi-submersible heavy lift ship is the biggest in the world, capable of carrying cargo weighing up to 117,000 tonnes. Hyundai Heavy Industries built it to transport offshore oil and gas platforms. However, it can also move other vessels and function as an offshore dry dock facility. This US $240 million vessel is 275 m long and 79 m wide, with a draught of 11 m when sailing and 31 m when submerged. Image Credits: Wikipedia Boka Vanguard’s bridge and living spaces are on the starboard side, and its watertight deck enables water to flow over it without risk. It is submersible, so it can lift vessels or rigs out of the waters and place them into the waters. When its ballast tanks are flooded, the deck becomes 16 m below the surface, enabling it to handle cargoes with a deep draught. Cargoes are floated over her, and her ballast tanks are empty, enabling Boka Vanguard to lift and ship heavy cargo. It can attain a speed of 14 knots and accommodate 40 crew members. 2. MV Xin Guang Hua This is the biggest Chinese Ship of her type and the second-biggest semi-submersible heavy lift vessel in the world, capable of carrying 100,000 tonnes. It was built by Guangzhou Shipyard International and is owned by COSCO Shipping. Construction started in 2015, and the ship entered service in December of the following year. Image Credits: Wikipedia Xin Guang Hua is 255 m long, 68 m wide, and has a 10 m draft. Its gross tonnage is 84,239 tonnes, and its cargo dock is 208 m long and can be submerged to a 16 m depth. It can undertake stern and side loading and was designed to have great internal strength. It has a diesel-electric propulsion system and six generators. The ship has a speed of 13.5 knots. 3. MV Blue Marlin Operated by Dockwise Shipping, Blue Marlin is a versatile ship built to transport oversized and heavy cargoes, such as offshore drilling rigs, container ships, naval vessels, etc. Blue Marin can carry 76,061 tonnes and has 38 cabins that accommodate 60 people. It also boasts state-of-the-art workout rooms, a swimming pool, a sauna, and a citadel to protect against pirate attacks. Image Credits: Wikipedia It was constructed by CSBC Corporation, Taiwan, in 2000 and has been a part of many crucial operations. US Navy hired it to transport destroyer USS Cole to the U.S after it suffered damage in a terrorist attack in Yemen. It also delivered the 60,000 tonnes Thunder Horse oil platform to Texas. Blue Marlin was refurbished in 2003, improving its manoeuvrability. This enormous ship measures 224 m lengthwise and 63 m breadthwise, and its deck covers more than 43,000 m2. 4. Seaway Hawk It is one of the world’s largest semi-submersible heavy lift vessels, designed for offshore and onshore facilities, with float on/off, roll on/off, skid on/off, and lift on/off operations. Seaway Hawk has an expansive deck measuring 157 lengthwise and covering 8700 m2, which can accommodate 40 people. Image Credits: seaway7 With its massive deck and high-capacity ballast system, it regularly moves the world’s largest and heaviest dr