Allseas Selects Vuyk for Semi-Submersible Design

Offshore industry leader Allseas selected Dutch maritime design house Vuyk Engineering to design its new semi-submersible Heavy Transport Vessel (HTV) ‘Grand Tour’. Purpose-designed to support seamless topsides transfers to ‘Pioneering Spirit’, the vessel represents a major step forward in integrated offshore transport and installation solutions. Built at Guangzhou Shipyard International, the new HTV is scheduled for entering service in Q1 2028.

The vessel is optimized by Vuyk to carry payloads of up to 60,000 tons. It is also designed to load and transport topsides of up to 40,000 tons at the stern and to fit precisely into Pioneering Spirit’s bow slot, enabling safe and efficient offshore handovers. Its semi-submersible hull, with a 57-meter beam, ensures enhanced stability and shallow-draft access to global fabrication yards.

Key design features include:

• 180 x 57 m cargo deck designed for direct skidding, roll-on/roll-off, and float-on/float-off operations;
• Methanol-ready propulsion system;
• Air lubrication system and podded propulsion to reduce fuel consumption;
• High-capacity ballast system for precise load transfers.

Main dimensions of the vessel are:

• Loa229.9 m
• Beam (moulded)57.0 m
• Depth (moulded)14.8 m
• Draught (summer)11.1 m
• PositioningDP2
• Propulsion thrusters4 x 3,500 kW
• Retractable thruster1 x 2,600 kW
• Tunnel thrusters2 x 2,000 kW
• Deadweight (11 m)73,000 t
• Deck space10,260 m²
• Transport capacity40,000 t at the stern 

Heavier cargos (up to 60,000 t) possible depending on optimal load spreading:

• 60,000 t @ 20 m COG above keel
• 49,000 t @ 30 m COG above keel
• 43,500 t @ 40 m COG above keel
• 38,500 t @ 45 m COG above keel