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The thrilling world of speed-sailing is responsible for some remarkable engineering innovations.

Back in September 2009, L’Hydroptere, a 60ft trimaran that ‘flies’ above the surface on two fin-shaped hydrofoils, set a new world record for D-class vessels of 51.36 knots.

More recently, The Engineer reported on the Vestas SailRocket II, a glider-inspired boat with designs on the outright unpowered 500m record of 55.65 knots.

Now, in a bid to push the performance of extreme sailing boats even further, a team of Scottish engineers is using advanced simulation software to design and develop a bizarre-looking vessel that the engineers believe could soon break the near-mythical 60-knot barrier.

The boat, dubbed the V-44 Albatross, is the brainchild of Tim Clarke, engineering team leader at Scottish engineering consultancy Prospect Flow Solutions and founder of Verney Yachts.

Clarke explained that his idea was to create a single-hull craft and equip it with two wing-sails — structures that are literally a cross between a wing and a sail.

Made from composite materials, these wing-sails are able to switch both position and function as the boat tacks, becoming either a wing if horizontal to
the water or a sail if vertical.

The approach has been tried before. The BMW Oracle, a trimaran sailboat, crushed its America’s Cup competitor in February 2010 using a wing-sail, while the Greenbird, a wing-sail-equipped land-yacht, set a new wind-powered land speed record of 126.4mph back in March 2009.

One of the challenges of developing a wing-sail is ensuring stability. While a conventional aircraft wing needs a tail to provide stability, this would add too much weight to a boat so wing-sail vessels typically achieve stability in other ways. For the BMW Oracle, a motorised trailing flap on a two-part structure was used, while the Greenbird deployed counterweights on the leading edge.

‘Abaqus enabled us to quickly and efficiently visualise the effects of taking different approaches’

Tim Clarke, Prospect Flow Solutions

The V-44’s stability comes from the wing-sail itself. Each of the 13m-long wing-sails is comprised of two sections: an inner plank and an outer plank. While the airfoil shape is designed to be inherently stable, stability also comes from the use of counterweights — one for each plank.

These planks are aerodynamically and mass-balanced about their axes of rotation and are designed to weathercock, or find their own position in the airflow like a weathervane. The design of each plank is intended to mimic the behaviour of a tubular spar centred at the axis of rotation, which has no tendency to rotate under bending loads. If the wing-sail did rotate as it experienced bending loads, it would upset the boat’s aerodynamic balance. For this reason, a different structural approach needed to be taken when compared with a typical aircraft wing or wing-sail.

Without knowing whether the craft was feasible to build and without the opportunity to even construct a prototype, simulation software is critical to the success of the project. Therefore, to help translate the conceptual design into a physical reality, the team turned to Abaqus FEA from SIMULIA, the Dassault Systèmes brand for realistic simulation.

This software enables the engineers to test the boat’s performance virtually, using a 3D computer model to analyse the structural strength of components, their response to wind loads and the craft’s fluid and aerodynamic characteristics. The software also allows them to isolate, evaluate and optimise structures critical to performance, such as the innovative wing-sails.

Clarke and his team needed to consider many wing-sail design variables. ‘Abaqus enabled us to quickly and efficiently visualise the effects of taking different approaches,’ said Clarke. Early in the design cycle, the team created some of the key models within Abaqus first and used the extensive functionality within the software’s interaction module to simplify those models.

Because the wing-sail’s structure and function are so complex, the engineers split the analysis into three stages: the spar, the ribs and secondary structures, and the skin. At each stage, as they built up the structure and added complexity, they wanted to ensure that the wing-sail was acting like a tubular spar with no orientation preference.

For the load case, they chose the worst-case scenario: the wing-sail operating in the horizontal plane and the boat at high speed with minimum keel penetration in the water. This situation generates lift across the entire wing-sail, as well as the greatest bending loads.

The three analyses validated the wing-sail concept and the team is now engaged in extensive computational fluid dynamics (CFD) analyses of the aero- and hydro-dynamics of the boat using FlowVision HPC from Capvidia. ‘This process helps us tune the control system and virtually test the boat before it is constructed,’ said Steve Howell, CFD lead on the project.

Once the design is finalised, the V-44 Albatross will be constructed without the benefit of prototypes or wind-tunnel/tow-tank testing. The projected date for the speed-sailing record attempt is early 2013. The chosen site is the upcoming summer Olympics sailing venue in Portland Harbour in the UK.

Dassault simulation software helps engineers get their extreme sailing boat off the ground

The thrilling world of speed-sailing is responsible for some remarkable engineering innovations.

Back in September 2009, L’Hydroptere, a 60ft trimaran that ‘flies’ above the surface on two fin-shaped hydrofoils, set a new world record for D-class vessels of 51.36 knots.

More recently, The Engineer reported on the Vestas SailRocket II, a glider-inspired boat with designs on the outright unpowered 500m record of 55.65 knots.

Now, in a bid to push the performance of extreme sailing boats even further, a team of Scottish engineers is using advanced simulation software to design and develop a bizarre-looking vessel that the engineers believe could soon break the near-mythical 60-knot barrier.

The boat, dubbed the V-44 Albatross, is the brainchild of Tim Clarke, engineering team leader at Scottish engineering consultancy Prospect Flow Solutions and founder of Verney Yachts.

Clarke explained that his idea was to create a single-hull craft and equip it with two wing-sails — structures that are literally a cross between a wing and a sail.

Made from composite materials, these wing-sails are able to switch both position and function as the boat tacks, becoming either a wing if horizontal to
the water or a sail if vertical.

The approach has been tried before. The BMW Oracle, a trimaran sailboat, crushed its America’s Cup competitor in February 2010 using a wing-sail, while the Greenbird, a wing-sail-equipped land-yacht, set a new wind-powered land speed record of 126.4mph back in March 2009.

One of the challenges of developing a wing-sail is ensuring stability. While a conventional aircraft wing needs a tail to provide stability, this would add too much weight to a boat so wing-sail vessels typically achieve stability in other ways. For the BMW Oracle, a motorised trailing flap on a two-part structure was used, while the Greenbird deployed counterweights on the leading edge.

‘Abaqus enabled us to quickly and efficiently visualise the effects of taking different approaches’

Tim Clarke, Prospect Flow Solutions

The V-44’s stability comes from the wing-sail itself. Each of the 13m-long wing-sails is comprised of two sections: an inner plank and an outer plank. While the airfoil shape is designed to be inherently stable, stability also comes from the use of counterweights — one for each plank.

These planks are aerodynamically and mass-balanced about their axes of rotation and are designed to weathercock, or find their own position in the airflow like a weathervane. The design of each plank is intended to mimic the behaviour of a tubular spar centred at the axis of rotation, which has no tendency to rotate under bending loads. If the wing-sail did rotate as it experienced bending loads, it would upset the boat’s aerodynamic balance. For this reason, a different structural approach needed to be taken when compared with a typical aircraft wing or wing-sail.

Without knowing whether the craft was feasible to build and without the opportunity to even construct a prototype, simulation software is critical to the success of the project. Therefore, to help translate the conceptual design into a physical reality, the team turned to Abaqus FEA from SIMULIA, the Dassault Systèmes brand for realistic simulation.

This software enables the engineers to test the boat’s performance virtually, using a 3D computer model to analyse the structural strength of components, their response to wind loads and the craft’s fluid and aerodynamic characteristics. The software also allows them to isolate, evaluate and optimise structures critical to performance, such as the innovative wing-sails.

Clarke and his team needed to consider many wing-sail design variables. ‘Abaqus enabled us to quickly and efficiently visualise the effects of taking different approaches,’ said Clarke. Early in the design cycle, the team created some of the key models within Abaqus first and used the extensive functionality within the software’s interaction module to simplify those models.

Because the wing-sail’s structure and function are so complex, the engineers split the analysis into three stages: the spar, the ribs and secondary structures, and the skin. At each stage, as they built up the structure and added complexity, they wanted to ensure that the wing-sail was acting like a tubular spar with no orientation preference.

For the load case, they chose the worst-case scenario: the wing-sail operating in the horizontal plane and the boat at high speed with minimum keel penetration in the water. This situation generates lift across the entire wing-sail, as well as the greatest bending loads.

The three analyses validated the wing-sail concept and the team is now engaged in extensive computational fluid dynamics (CFD) analyses of the aero- and hydro-dynamics of the boat using FlowVision HPC from Capvidia. ‘This process helps us tune the control system and virtually test the boat before it is constructed,’ said Steve Howell, CFD lead on the project.

Once the design is finalised, the V-44 Albatross will be constructed without the benefit of prototypes or wind-tunnel/tow-tank testing. The projected date for the speed-sailing record attempt is early 2013. The chosen site is the upcoming summer Olympics sailing venue in Portland Harbour in the UK.

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