Feasibility study

Summary of the test results from the perspective of HEIG-VD (April 24):

• In principle, the combination of two sustainable energy resources (such as solar & wind) in one element such as the SOLARRIG, which combines direct propulsion by wind power and the conversion of solar energy into electrical energy for propulsion and on-board systems, offers the following advantages over "sails only" or "solar cells only":
• • A) as the tilting and pitching structure provides virtually any configuration needed for conventional sailing,
  • B) while at the same time utilising the sun's energy even at a flat angle of incidence (and providing shade at anchorage or in the harbour and still capturing solar energy)
  • C) also provides buoyancy due to its angle to reduce displacement drag. This minimises the usual sinking of the bow in high waves and thus increases safety.
• This sail shape as a crab claw combined with the latest technology is the best compromise for converting wind power into propulsion and solar energy into electricity. This shape, traditional in the South Pacific, is particularly efficient, as the air turbulence near the boat is less disruptive and the wind in the upper area enables even more effective propulsion and lift. This means less sail area >> less material >> less wear and tear.
• Translated with www.DeepL.com/Translator (free version)

Efficiency:

• At 25 kn downwind, the SOLARRIG offers more than twice as much power as conventional electric motors: i.e. the simulations show an equivalent SOLARRIG output of between 7.5 and 9 kW from the configurations. As the boat only needs 2.5 kW of motor power at 5 kn, the equivalent forward thrust at a wind speed of 25 kn and a boat speed of 5 kn is between 7.5 and 9 kW.

Optimisation:

• Considering the prevailing winds, the efficiency depends on the curvature of the wing: the higher the sail curvature, the higher the efficiency. According to the preliminary simulations, the optimum is 8%. Screenshot of the optimum wing curvature.
• A second element to take into account is the "margin", which is considered 0 in the simulation, as if the boat were travelling on rails, which is not realistic. This means that the catamaran, like any sailing catamaran, needs two keels to counteract the drift. This converts part of the sideways energy into propulsion.

Limits:

• The limits of this concept result from the boat geometry in terms of size and topology. On larger vessels, several SOLARRIGs may be mounted in a row instead of one very large, heavy sail. - This should be worked out using the configuration software (= configurator) and the control and alarm software (= informator and digital twin) for x-which ships.

Disadvantages:

• Conceptually there are no disadvantages, this is the best of both worlds, with one element (SOLARRIG) being used for power generation and propulsion.

Proof of Concept:

• The SUNsation 52 catamaran, with its planned test runs in the Mediterranean and across the Atlantic, is a great platform for a proof of concept to be installed and tested as an intermediate size between superyachts (80+ feet) and the market for catamarans from 30 to 45 feet.