In July this year, the Royal Boskalis Westminster owned semi-submersible heavy lift vessel BOKA Vanguard loaded the LOA 324m x 37m beam cruise ship Carnival Vista for drydocking and repair of the vessel’s azipod propulsion system in the Grand Bahama Bahama shipyard Freeport, Bahamas. The unusual operation was an emergency solution to the closure of one of Grand Bahama Shipyard’s three drydocks following a crane collapse which damaged Royal Caribbean’s Oasis of the Seas.

With an open deck measuring 275m x 70m, the uniquely designed Boka Vanguard is the world’s largest semi-submersible heavy lift vessel and since first commissioning has been extensively used to move large and heavy offshore oil and gas structures around the world.

• Built by Hyundai Heavy Industries, Ulsan, South Korea in 2012
• Owned and operated by Dockwise Shipping B.V.
• LOA 275m
• Beam 79m
• Operating draft 15.5m, submerged draft 31.5m
• GRT 91,784 tons
• DWT 116, 173 MT
• Propulsion: Twin propellers, two retractable azimuth thrusters, single bow thruster
• Speed 11 knots loaded, 14 knots in ballast
• Crew 40
• Construction cost US$ 240m
• Original name Dockwise Vanguard
  

See a video of the loading operation

https://www.youtube.com/watch?v=cm2cAs445wU

As can be seen from the video, Boka Vanguard features a bow-less design with the crew accommodation, including the lifeboats, on the starboard side of the vessel. The design allows water to flow along the entire deck but prevents flow into the enclosures of the vessel. Engine exhausts are based on towers at the port and starboard quarters.

The 4,000 guest capacity Carnival Visa was built by Fincantieri, Monfalcone, Italy and entered service in 2016. She is fitted with two ABB Azipod units and has a service speed of 18 knots