The maneuver was enormous, so an ally of the same caliber was needed: enormous. In May 2022, the Acciona company encountered a considerable challenge in the waters of A Coruña. One of those tests the skills of engineers. Its workers had been in charge of creating six gigantic concrete caissons weighing 15,000 tons each, enormous masses 60 meters long and 24 meters wide designed for the expansion of an airport in the Philippines. Once completed, the challenge, of course, was how to move those six blocks totaling 90,000 tons to their destination, thousands of kilometers from the Galician coast.
Their solution: call the BOKA Vanguard – formerly known as Dockwise Vanguard—considered the largest semi-submersible heavy cargo ship in the world.
The strongman of the seas
The BOKA Vanguard is often considered the largest boat in its category. And it has the strengths to be. The Vanguard is a heavy-lift semi-submersible vessel designed for two main purposes: transporting large structures across the oceans, which includes FPSO units, floating platforms for oil exploitation, other ships or gigantic concrete blocks such as those manufactured by Acciona in A Coruña; and serve as a dry dock to inspect and repair structures in the middle of the ocean.
In either case, the work of the BOKA Vanguard is more or less the same: it carries very heavy loads of tens of thousands of tons on its shoulders.
Muscle for 10,000 tons
If the BOKA Vanguard can handle such tasks, it is largely due to its muscle and design. As she demonstrated in A Coruña, she is capable of loading tens and tens of thousands of tons. To be more precise, 110,000, even more than the Blue Marlin, another semi-submersible vessel that has carried out delicate operations in the waters of northern Spain.
To carry such loads, the BOKA Vanguard is equipped with good “backs”: it has a large deck that extends the length of the boat and allows it to accommodate huge structures. The ship measures no more and no less than 275 m in length by 70 m in width with a depth of 15.5 m. Her dead weight (DWT) is around 116,000 t and reaches a maximum of 14 knots.
A lot of strength, and skill. Not everything is strength, of course. If the BOKA Vanguard is capable of handling such loads, it is thanks to its design and how it approaches stowage operations. The ship can be ballasted underwater, which leaves its deck submerged and makes it easier for cargo to remain floating in the right spot.
When this maneuver has been completed, the BOKA Vanguard releases ballast, raises the deck again and lifts the load. The operation is possible thanks to its tanks and structure, designed so that the water flows through the ship without entering its compartments. Both the crew and the boats are located to starboard.
Beyond theory. It’s not all theory.
The maneuver that he carried out in 2022 in the waters of the outer port of Punta Langosteira, in A Coruña, is a good example. When the BOKA Vanguard arrived at the place reserved for the maneuver, it partially sank so that the half-dozen 15,000-ton caissons could be moved, one by one, until they were floating on the submerged deck.
“The ship was then refloated and moved to the Ares estuary, where preparations were made to secure the caissons before leaving for the Philippines,” Acciona recalls. The Port Authority of A Coruña claimed that never before had 90,000 tons been reached in a single shipment. The BOKA Vanguard manages a draft of 11 meters when she is sailing and 31.5 when she is submerged.
And more than a whim. That the Boka Vanguard is equipped with such a capacity goes beyond a simple whim or the search for a new record in maritime logistics. If in 2010 Dockwise decided to order a vessel capable of outperforming its predecessors, it was to meet the needs of offshore operations, which required moving huge constructions across the oceans.
The greater the capacity, the more structures they can move and the lower the costs of moving components that later have to be assembled at their destination. The order fell to Delta Marine, DNV and Hyunday Heavy Industries and the ship took shape in Korea between September 2011 and November 2012.
Years later and after a business change, its name changed from Dockwise Vanguard to Boka Vanguiard. In 2018, when announcing the new designation, Boskalis boasted of its enormous capacity: “It is the largest semi-submersible heavy lift vessel in the world and is preparing to load a 90,000-t floating platform, which is equivalent to the weight of approximately 300 Boeing 747”.
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Source: Reutir
