Boka Vanguard is a semi-submersible heavy transport vessel capable of carrying cruise ships weighing over 100,000 tons.
The Boka Vanguard can easily transport cruise ships on its deck. (Video: Boskalis)
Constructed in 2012, the Boka Vanguard measures 275 meters long, making it the largest vessel of its kind. Typically, the ship transports large offshore oil and gas structures, but it is sometimes called upon to carry other vessels, such as the Carnival Vista.
The Carnival Vista is the second-largest ship in the Carnival fleet, capable of carrying 4,000 passengers and a crew of 1,500. In July 2019, the ship required rescue after encountering mechanical issues in the Caribbean Sea. A crane was not a suitable option for lifting the 133,500-ton vessel out of the water, as the largest crane in the world can only lift about 20,000 tons. Therefore, the Boka Vanguard employed a different method.
The Boka Vanguard has a peculiar shape, featuring a flat and completely empty central deck with five large vertical structures protruding from the sides. The bridge and crew living quarters are located in one of these structures. The unusual design conceals a complex ballasting system that allows the ship to partially submerge, with only the tops of the vertical structures above water. Various types of floating cargo, including cruise ships, can slide onto the Boka Vanguard’s deck.
After securing the cargo on deck, the ballast system releases water, allowing the Boka Vanguard to rise again, lifting the heavy load high. The vessel then begins its journey just like a regular ship. Upon reaching its destination, the process is reversed. Michel Seij, Global Technical Director at Boskalis, the Dutch company that owns the Boka Vanguard, shared that they utilize Archimedes’ principle of buoyancy in the ship’s design.
The Boka Vanguard has a peculiar shape.
In addition to participating in various specialized marine missions, ranging from dredging to offshore construction and wind farm installation, Boskalis operates the largest fleet of semi-submersible heavy transport vessels in the world. For instance, Boskalis vessels assisted in the transportation of two Arleigh Burke-class destroyers of the U.S. Navy after both were damaged in separate collisions with merchant ships in Asian waters in 2017, namely the USS Fitzgerald (DDG-62) and the USS John S. McCain (DDG-56). In that instance, the rescue did not involve the Boka Vanguard but rather two smaller vessels named Transshelf and Treasure.
In the case of the Carnival Vista, the need to deploy the Boka Vanguard arose when the ship’s propulsion system malfunctioned, and the nearest dry dock was not nearby. The Boka Vanguard easily transported the 325-meter-long Carnival Vista on its deck, functioning as a mobile dry dock, allowing for maintenance work to be carried out.
