The different parts are hand crafted by the 16 teammembers. The boat suffered from the lack of test trials since there were just two of them before the race started.

Have a look at some pictures by clicking on this link.

A summary of the main technical data

Solar cells

The boat is supplied with Galium-Arsenide Advanced Triple-Junction solar cells. These cells are normally used in space but are also very suitable for racing applications because of its high efficiency. Our cells have an average efficiency of 22,9%. In total, there are 2720 of these cells on the deck, worth approximately 7.5 m2. This solar panel produces a maximum power of 1750Watt, provided that the sun is shining well of course. The energy that comes from these cells is conducted to the maximum power point Trackers (MPPT’s). These MPPT ensure that the power extracted from the cells is continuously at its maximum.

Electrical system

The boat uses Lithium Polymer battery cells. This type of battery has a high energy density, which means that you minimize weight and maximize the amount of energy that can be saved. The total capacity of the battery pack is 1 kilowatt-hour and weighs at around 6kg. This package can be fully charged in just over 30 minutes by the solar panel and is thus comparatively small. It is therefore mainly used as a buffer between the solar panel and motor, rather than being a major source of energy. During the trip, the motor uses energy of the solar panel in the first place. In case more energy is produced by the solar panel than needed, the additional energy is stored in the battery pack. This energy can then be used later when it is cloudy or just when the boat is sailing at top speed just before the end of the race.

Drivetrain

The drivetrain starts with the motor controller. A signal is sent to this device in order to control the motor. The engine will supply a certain amount of power which is linked to a certain number of revolutions and torque. Between the screw and the motor is still a gear box, with which the speed of the motor is converted to a suitable rotational speed for the screw. The motor controller, motor and gearbox are made in Germany and the system can deliver up to 4 kW of power.

All this comes in a so called ‘pod’. This pod is manufactured in collaboration with DEMO and is made from aluminum. New to the pod this year is that the engine with its controller and gearbox are all installed in this small shape. Ard made ​​sure that everything fits well and he has also designed a system for the hydrofoils to steer. This is done with the help of two linear actuators which are inserted the rear of the pod.

Propulsion

Because this year hydrofoils are used and the team also wants the boat to sail well without hydrofoils, two different screws are designed to fit both conditions. The screw for sailing without hydrofoils is designed by MARIN. This screw looks very much like the old (2008) screw. With the design is based on the needed strength of the screw and the diameter is decreased.

The screw that is designed to sail on hydrofoils is designed in collaboration with Wärtsilä Netherlands. This screw looks quite different than the screws from previous boats. The main different is that this screw has an smaller diameter. The screw used for the contest in 2008 had a diameter of 50 cm. The two screws for the new boot have a diameter of 34 cm. This is done so, because the screw would pierce the surface when sailing on its hydrofoils.

What is striking about the new screw design is that the chord of the blades is much more variable in the new design and there is added some ”skew” to the. This is the curvature in the blade so that the blades appear more like a moon.

Hull

The hull was developed in collaboration with MARIN (Maritime Research Institute Netherlands), the largest marine research institute in the world. This year the design of 2008 is developed further. The reason why there is not innovated on the hull shape is that we are planning to sail mainly on the hydrofoils.

Because of the innovative hull shape, the resistance in the water is minimal. The weight of the boat is very important for the resistance. This is also minimized, partly because the boat is built of carbon fiber. This has resulted in a hull shape with a very low resistance in the water, by using a depth of only 12 cm and the narrow shape below the water surface.

Compared to the previous design, a number of changes has been made. One of the biggest changes has to be the good tuning of the shape on the actual weight of the boat. A second adjustment that is carried out is the adaptation of the ship above water. The boat did just meet the stability requirements of the competition last year. After adjustments to the underwater hull, this has become even more critical. The topsides are somewhat rounder to stabilize the boat faster when it is stilted. Also, the stern is made completely flat, and the curvature is removed from the deck.

Hydrofoils

In 2010 the risk was taken for the first time to sail on hydrofoils. Hydrofoils ensure that the boat is lifted from the water when it reaches a certain speed. The boat flies virtually across the water. Because a large part of the boat is lifted from the water, there is much less resistance. This means that the same power could result in a top speed that is 1,5 times as high as before.

The hydrofoils are also developed in collaboration with MARIN. The team is supported by a wide variety of advices and was allowed to use specially developed software from Marin.

At the bow the boat is supported by V-shaped wing. This is a surface-piercing hydrofoil which ensures that the boat can stabilize autonomously. At the back of the pod a hydrofoil is attached with a T-shape. This is called a fully-submerged hydrofoil. This wing can also be controlled, so we can adjust angle of the wing to make maneuvering easier.

Safety

The Solar Boat also has a number of safety systems. Thus, the battery is constantly monitored for its temperature and voltage by the batterymanagement system. This system can be tracked and if necessary, this can be followed by an intervention. There also a fire extinguishing system on board that is automatically activated when the temperature in the boat too high. Next, if any unexpected water gets in the boat, the bilge pump will automatically pump the water out. It is also possible to turn the pump on manually. In the cockpit the sailer is connected to a dead mans switch. This switch will turn the whole system off in case of emergency. During the match a wireless connection is set up to a support vehicle in which the operation of the system, battery reserves and the weather conditions are monitored and analyzed. This is very profitable for the strategy department. The boat is then also a tracked to follow determine the correct speed and position. To  protect the boat better from short circuiting almost all systems are waterproof.

A summary of the main technical data:

Solar system
The 8 m2 deck area of the boat is covered with 2964-Galium Arsenide Triple Junction solar cells. These cells have an efficiency of 25% (normal cells have an efficiency of approximately 15%). Galium arsenide is one of the most efficient semiconductors, but the material is very scarce and very expensive. These solar cells are mainly used on satellites. Four electronic control units (MPPT’s, Maximum Powerpoint Trackers) ensure the continuous maximum power from the solar cells is achieved.

Electrical system
If the solar panels generate more energy than is needed to drive the motor, the excess is stored in a 6 kg rechargeable (lithium polymer) battery. The solar boat is driven by an electric motor with a perpendicular gear box and is connected to a two-blade propeller. The gear box is located in the ”pod”, a streamlined underwater cabinet. If the driver turns the carbon wheel, a steering cable ensures that the entire motor and pod combination including gearbox and screw rotates (no rudder). In this way the boat is able to make very sharp turns. The Solar Boat also has a number of safety systems. Thus, the battery is constantly monitored for its temperature and voltage by the batterymanagement system. This system can be tracked and if necessary, this can be followed by an intervention. There also a fire extinguishing system on board that is automatically activated when the temperature in the boat too high. Next, if any unexpected water gets in the boat, the bilge pump will automatically pump the water out. It is also possible to turn the pump on manually. In the cockpit the sailer is connected to a dead mans switch. This switch will turn the whole system off in case of emergency. During the match a wireless connection is set up to a support vehicle in which the operation of the system, battery reserves and the weather conditions are monitored and analyzed. This is very profitable for the strategy department. The boat is then also a tracked to follow determine the correct speed and position. To  protect the boat better from short circuiting almost all systems are waterproof.

Hull
The design of the hull is done in cooperation with the largest marine researchinstitute in the world, MARIN. The Solarboat has a very narrow part underwater (the depth is only 10 cm) so that the resistance of the hull is minimal. The hull above the water is wider to meet the surface needed for the solar cells. The boat is made of carbon. In the deck glass fiber mats are used in because of the conductivity of carbon. These materials are strong and ultra light. The lower the weight, the faster the boat can sail. The hull is reinforced with five transverse bulkheads and a flat cover edge. The hull is relatively weak. Only when the hull is connected to the deck, a rigid (box-) structure is created. The nose of the bow is razor sharp in order to ‘cut’ through the water and is reinforced with an aluminum plate to resist a possible collision. In the corners are four stiffeners with lifting eyes attached to it to be able to lift the boat out of the water.