High speed solar ship

High speed solar powered ship

Figure 1. Hydrodynamic and Aerodynamic WIG (HydAer) to solar energy. This type of ship can reach speeds of 200 to 230 km/h compared to the 80 to 100 km/h maximum speed that current high-speed ships can reach.

HydAer WIG or Naval Vehicle in Ground Effect Propelled totally or partially to Solar Energy

In order for a boat to be able to operate on solar energy, it needs a surface for capturing the sun's energy several times greater than the size of its own hull, for this it is necessary to put an additional structure to increase the surface for capturing solar energy and where to place the photovoltaic solar panels to generate the electrical energy necessary for the operation of the boat, both for its propulsion systems and for the energy consumption of the different equipment that it carries.

In the case of boats that need to navigate at high speed, a system that may be suitable to be able to expand the solar energy collection surface is a system of folding wings on both sides of the main hull. Where said structure will also have floats on its sides to be able to support the weight of said solar panel carrier structure when it is deployed and extended.

To reduce the energy consumption of the ship when it navigates at high speed, it may be convenient that the structure that is deployed to be able to capture a greater amount of solar energy also has the shape of the wing of an airplane, since when this ship navigates at high speed A lifting force will appear on the wings of the ship that will tend to raise the ship's hull and reduce the contact of the water with its surface.

As the kinematic viscosity and density of water is greater than that of air, at high speed, the drag force produced by the water on the hull of the boat will be greater than the force produced by the air on the wings of the boat. boat, therefore, it is better that this boat when sailing at high speed has as little contact and friction as possible with the water.

In addition, when the wings of an airplane move on a flat surface at a very low height (between 0.3 and 3 meters), an overpressure of the air appears under the wings of the airplane that increases its lift force and reduces its energy consumption between 40 to 60% of when the plane is traveling at a conventional height. This effect is also used by WIG (Wings In Ground effect) or ground effect vehicles that function as if it were an airplane in low flight.

Figure 2. The hulls that you can have will be like those used by current high-speed boats such as planing hulls, catamarans or hulls with hydrofoils..

Efficiency of solar panels

At this time the maximum efficiency of commercial solar panels is in the order of 20 to 21% although there are space-use solar cells that would be very expensive to use in this type of ships with efficiencies of the order of 35 to 40% . The maximum efficiency that a multijuncture or tandem solar cell could have is 68,2% and solar cells of silicon quantum dots are currently being developed in laboratories with the potential to reach efficiencies of the order of 40-50% in the coming years, therefore for the calculations and estimates of the consumption that we will carry out in this article we will consider 50% efficient solar panels which is an efficiency that solar panels may have in the not too distant future.

Laboratories around the world are working on new types of solar cells, how the called Phonovoltaic Solar Cell that have the theoretical potential to reach efficiencies close to the Carnot Limit of 95%. So, it can be expected that at some point 50% efficiency will be reached, if not exceeded.

Therefore, for the calculations in this article, we will consider solar panels with an efficiency of 50%.

Propulsion and operation systems at different speeds

In this type of boat, the most advisable is that its propulsion system is made up of electric motors since they are smaller than internal combustion engines and they can also work submerged in water and be placed next to the propellants used. As propellants, the most convenient thing is to use high-speed propellers, supercavitating propellers or high-efficiency water jet systems, which are the propulsion systems used in today's high-speed boats.

In general, the consumption of the boat will increase with the weight of the transported load and its speed, therefore this boat may have two main ways of operating one at low speed, where 100% of its energy consumption may be supplied by its own solar panels, reaching speeds of approximately 30 km/h. And another operating at high speed where the wing shapes of the solar panel holder structure and the ground effect that will occur under them will allow it to operate with a markedly lower energy consumption and also reach higher cruising speeds than the boats of current high speed.

Likewise in its operation at high speed, although the total consumption of the boat depends on the total weight of the same and the weight of the transported load, it is most likely that it cannot work only with the energy supplied by the solar panels but rather needs an auxiliary electrical energy, which may be delivered by a system of electrical accumulators that are recharged with external recharging systems to the boat at the docks or at the anchoring places of the same.

The advantage that this type of vessel may have over the aerial WIGs that are also currently being developed is that the underwater thrusters will give it greater thrust and greater braking capacity when the vessel is cruising at low speeds and making its acceleration and deceleration movements in a better way since this boat will always have its propellers submerged in the water, and that in the case of aerial WIGs they take off and land as seaplanes currently do and it is a slower and more complex way to do acceleration, deceleration. Also another advantage that this type of propulsion with aquatic propellers has is the avoidance of packages or other vessels that may be in the water in the path of this high-speed vessel, which this vessel with underwater propellers that would give it the ability to improve the handling and maneuverability of the boat at high speed in those moments, since in aerial WIGs to avoid an obstacle or another vessel in the water the WIG must accelerate and increase the power of its engines by double or triple its regime power to get out of ground effect and be able to increase its height and avoid the obstacle, and this can make it very dizzying and dangerous when avoiding other boats or obstacles that are on the water, while in these WIG HydAer to avoid an obstacle these boats would first slow down and slow down slowly and progressively so that there is not a very abrupt deceleration with the water, like any current high-speed craft, and then it would dodge the obstacle or the other craft and they would increase their speed again to continue their journey at high speed, being a much safer way to avoid these types of obstacles or other craft than the aerial WIGs and this is possibly the main operating advantage between these two similar types of ground effect transportation systems that travel on water.

Figure 3. The width of the wings and their size can be adjusted to each application. The side floats also serve to pocket the air under the wings and increase the ground effect.

Although at present commercial solar panels have a limited efficiency of the order of 20 to 21%, lower than the efficiency that they may have in the future, today the use of this type of boat is also justifiable since the The use of solar energy will allow you to considerably save the external energy consumption of the boat, both when sailing at low and high speed, compared to the energy consumption that current boats have in these two types of uses.

Types of applications and areas appropriate for the use of this type of ships

Figure 4. The mooring and anchoring should be done so that the wind and waves do not affect the boat due to the significant height that the folding wing system can have when folded.

This ship, because it has the lateral wing system very close to the water when it is sailing with the structure unfolded and extended, and because it has a great height when the folding wing structure is folded, it may have problems when it is sailing if there are strong winds and waves. For this reason, it is most convenient for this type of vessel to be used in sheltered water areas or in open seas with light winds and with the precaution of not exposing this vessel to strong winds and waves such as storms.

In addition, this type of WIG HydAer that are propelled from the water can suffer a significant destabilization and difficulties in their maneuverability when the wind and waves are crossed and do not coincide with the direction of movement of the WIG propelled from the water. For this it is necessary to make your water thrusters "Steerable" to accommodate the wing structure to each wind condition that exists at all times.

Types of applications of this boat:

1_ In pleasure or leisure yachts, and in sports or fishing boats with a length greater than 10 meters. In this case, when these boats move at low speed, they will be able to do it 100% with solar energy and if they need greater speed for their movement, they will be able to do so at a higher speed than current high-speed ships. In addition, when they are at anchor or without movement, they can take advantage of recharging the electric batteries that they carry with the extended solar panel wing structure.

2_ In police or military ships for patrolling coastal areas. Being able to navigate both at low and high speed as needed during their patrols or chases.

3_ In Ferries for the transport of people or loads from short to medium or long distances.

This type of high-speed boat has as its most interesting application the possibility of being able to reach speeds of around 200 to 230 km/h in naval vessels propelled from the water, in which these speeds cannot be reached by any other type of vessel, such as Catamarans, Planing Hulls or Boats with Hydrofoils and they will probably be used especially in the aforementioned vessels where the reduction of the time necessary to make the boat trips is more important with short and medium-distance routes of the order of 1,000 or 2,000 km or more of autonomy navigating at high speed.

This would allow to increase the tourist use of the large Luxury Yachts and considerably reduce the time of the tours and the trips in Ferries among other advantages of the use of these high-speed ships.

Figure 5. The wing structure in a folding shape will allow you to expand the solar energy collection surface when it is sailing and reduce its size when it is moored or anchored.

Stability and maneuverability of these ships with winds and cross waves.

The ground effect vehicles that use water propellers as propulsion systems, in general, have drawbacks in the stability and maneuverability of the boat when it moves at high speed with winds and cross waves, as was the Ferry project Seabus-Hydaer of ground effect and high speed investigated by the European Union between 1997 and 2000 and which was frozen and abandoned after finding significant drawbacks in the maneuverability and stability of this type of boat when the boat is moving at high speeds with cross winds and waves. 

This Ferry Seabus-Hydaer investigated years ago by the European Union, used gas turbine combustion engines and water jet propellants for its propulsion and had a design speed of 125 knots (231.5 km/h) and could transport 800 people and 100 cars.

Figure 6: Ground effect boat powered by electric motors and propellers composed of surface piercing propellers or water jet systems.

 

One way to reduce the harmful effect of crosswind action against the lateral stability of the boat when moving at high speeds is by using multiple propulsion systems, each consisting of electric motors and propellers with Azimuth control systems of the position of the propulsion systems, where each of the propellers has the possibility of changing the direction independently of each other but in a coordinated way among all of them to be able to orient the wing structure of the boat and be able to perform the turns and bending it in the desired way in order to "orient" the wing structure of the vessel at any time in the way necessary to avoid the harmful action of crosswinds on the lateral sides of its wing structure.

Figure 7: Ground effect vessel with supercavitant propellers and hydrofoils oriented to move in the same direction as the wind and waves.

 

 

When this ground effect boat is moving for or against the wind but with a direction that coincides with the direction of the wind, all the propulsion units formed by the electric motor, the propeller and the hydrofoil will all be "oriented" in the same direction as the direction of movement of the boat, as shown in Figure 7.

Figure 8: Wind directions acting on the wing structure of the vessel when there are winds and swells cross.

 

 

But when there are winds and cross waves to the direction of travel of the vessel at high speed, as in this example of Figure 8, the angle between the direction of travel of the vessel and the Resultant of the wind acting on the wing structure of the boat, which is what most complicates the lateral stability and the maneuverability of the boat, is 8 °. Therefore, if we rotate “all” the independent propulsion units formed by the electric motors and the propulsion propellers that same angle, both in the bow and stern thrusters (as shown in Figure 9), the direction of the wing structure of the vessel will be "aligned" with the direction of the resulting wind acting on the vessel, thereby minimizing the harmful effects of lateral destabilization of the crosswind on the wing structure of the vessel, being able to significantly improve the stability and maneuverability of the boat, and it will also improve and decrease the value of the resistance to advance generated by the wind and the cross waves when it acts on the boat at high speed.

Figure 9: Ground effect boat with supercavitant propellers and hydrofoils oriented to move in a different direction than the direction of the wind and waves.

With this independent rotation system of the propulsion systems to "align" the wing structure of the boat with the resulting wind direction that acts on its wing structure when the boat moves at high speed, we will reduce the harmful effects of the wind on the boat, but we will not completely diminish the harmful effects that the cross wave will also have on the underwater propulsion systems of the boat, but in general, the effect of the cross wave on the immersed jets in the water (once resolved the harmful effect of the cross wind over the wing structure of the ship) will be similar to the effects and destabilization generated by the cross waves in vessels only with hydrofoils, and whose effect is often practically negligible in the operation of such vessels only with hydrofoils.

With this steering system of the wing structure of the vessel as needed, it will be possible to significantly reduce or directly solve the problems of stability, maneuverability and increased resistance to advance generated by winds and cross waves on the normal operation of the vessel. boat; But the cross waves with which this boat can operate should not exceed certain heights at which it is impossible for the boat to navigate with a high wave height that will also occur with the wind or the waves in the same direction of the boat.

Therefore, I think it may be interesting and necessary to study and investigate the application of this type of electric-solar propulsion system in this type of ground effect vehicles propelled by water propellers, given the interesting characteristics of high speed and relatively low energy consumption. that could have this type of high-speed vehicle, given the growing interest in the application of solar energy in naval transport systems and the fact that it is possible to use this type of ground-effect vehicles propelled by water propellers both in high speed ferries, such as large and medium recreational yachts, and coastal patrol or coast guard vessels.

High-speed propulsion systems.

Ground effect vehicles that use water propellers as propulsion systems were generally designed with fully submerged propulsion systems or propellers, such as the European Union Seabus HydAer project that envisaged the use of turbine-driven water jet systems gas and reach speeds of 125 knots (231.5 km/h). But in the case of water jet systems that are used in high-speed boats, the maximum speeds that they can generally develop is up to 60 to 65 knots (120 km/h), where from these speeds their efficiency of operation begins to decrease like almost all high-speed water propellers due to the appearance of the cavitation effect that begins to occur at high speed.

In the case of racing boats such as the international Class 1 category that reach speeds of the order of 140 knots (260 km/h), they use semi-submerged surface propellers for their propulsion, which can operate at said speeds with good efficiency, but the propeller has to work flush with the water with one part of the propeller submerged and the other part in the air, and with a specially shaped blade design that causes a reduction in the cavitation effect on the propeller blades propeller when they move at high speed.

In the case of this ground effect boat propelled from the water, when this boat if it is loaded or if it is empty, it can have different heights of its structure and its hull with respect to the water, or if there is a certain swell at the time of sailing high speed that also makes it difficult for semi-submerged propellers to be flush with the water at all times, it would be convenient if the water propeller used is completely submerged in the water at all times, but it is difficult to find aquatic propellers that work at high speed totally submerged with good efficiencies due to loss of efficiency due to cavitation.

I believe that in order to reduce the cavitation effect that is generated in the rear part of the propellers when their speed increases, it would be that pressurized air is injected in said rear part of the propeller to avoid the decrease in pressure that It occurs in these parts of the propeller when its speed increases and the appearance of cavitation decreases, making it possible to make propellers that can operate at high speed without loss of efficiency due to this effect.

In this case, I also believe that a study should be carried out to verify that this injection of pressurized air at the rear of the propeller correctly reduces efficiency losses due to cavitation in the case of using propellers with pressurized air injection, and it seems to me that it can be an interesting way of obtaining totally submerged propulsion systems with good operating efficiencies at the speeds that we would like these high-speed boats to navigate, which would be of the order of 200 to 230 km/h.

Consumption estimate

The fuel consumption per ton transported and the ratio of the transported load to the total weight of the loaded WIG that are given in the tables that show the figures are estimates and their values ​​depend on the efficiency of the ground effect that is achieved with the WIG during its operation, the own weight with which this boat is manufactured and the weight of the fuels or electric batteries used.

As the maximum ratio of the lift coefficients Cl and drag Cd is 65, for the chosen wing profile, we consider for the calculation of the fuel consumption of the boat to values ​​of the ratio R = L/D, of the order 30, 40 and 50.

Considering that a good ratio between the transported load and the empty dead weight of the vessel for short voyages can be 1,2 ; but if the trip is long distance, where it would be necessary to carry a lot of weight in electric batteries or fuel or if the own weight of this WIG HydAer would be high, the relationship between the transported load and the empty weight of this boat may fall to a value estimated 0.8.

In these results we can see that the estimated consumption for the WIG HydAer would be for travel distances of about 1,000 to 2,000 km and said consumption would be lower than the consumption per load transported by an airplane, but higher than the case of a truck or the rest of the systems of transport of great loads like the railroad or the interoceanic ships.

Conclusion

In principle, according to the results obtained, this type of WIG HydAer electric-solar would be justified as a use for the transport of light or intermediate loads, or of people in short and intermediate distances of about 1,000 to 2,000 km, as is the case of the Ferries current, luxury yachts or coastal patrol boats.

Although as the most determining value to determine the final consumption that this type of high-speed boat will have and the maximum autonomy that it can achieve, it will depend on the weight of said boat and this weight will largely depend on the type of electric battery that is used and that it is possible to obtain and manufacture in the future such as lithium, sodium or aluminum and graphene batteries that are currently being developed to achieve batteries with the lowest possible cost and weight. We also believe that current gas turbines can be used as propulsion systems, which have a very good Weight-Power ratio and use traditional fuels such as diesel and marine fuel oil, which weigh considerably less than electric batteries and can increase autonomy of these boats and exceed the 2,000 Km that one would think that these boats could have with electric batteries.

It should also be mentioned that it would be necessary and convenient to carry out an experimental prototype to check that this boat built in the way proposed here can work correctly as proposed in this project, being the two most important issues to check that they work correctly where in a first case it would be that the reduction of the lateral destabilization and an improvement in the maneuverability of the ship in the face of lateral or cross winds with the systems of multiple aquatic propellers guided by the Azimuth systems and in a second case that the totally submerged propulsive propellers manage to improve its propulsion efficiency at high speeds by injecting pressurized air into said propellers to avoid the formation of the cavitation in said propellers that cause their loss of efficiency at high speeds, or to also corroborate if it is possible to use as propulsion systems directly the ejection of pressurized air produced by an air compressor or by exhaust gases from gas turbines that would be used with traditional Diesel fuels.

We believe that this type of high speed ground effect boat as projected here can function correctly at the desired speeds of 200 to 230 km/h and with a fuel consumption that would be considerably less than if we not used the wing structure that takes advantage of the ground effect produced in a wing flying at low altitude. In addition, the fact that this ground effect vehicle is propelled from the water with supercavitating propellers and not from the air with aerial propellers, although when it moves completely from the air it may have lower consumption than with aquatic propellers and also the possibility of being able to move at high speed if there are strong or intermediate waves, we believe that propelling yourself from the water has a safer operation when you have to dodge an obstacle or some other boat in the water and that we believe is the most important feature that it is justified to make these high-speed vehicles propelled from the water and not from the air with aerial propellers or some other propulsion system in which the ship is not propelled from the water when moving at high speed.

We also believe that it would be interesting for this vessel to be used for high-speed cargo transport where we believe that above all it can be used for refrigerated and/or high-value cargo for intermediate or long distances of up to 4,000 or 5,000 km at a faster than current container ships and at a lower cost than cargo transported by plane.

Project progress status

At this moment I am trying to make an experimental prototype of this high speed electric-solar boat to be able to verify the feasibility of its correct operation and I am looking for interested parties in carrying out and being able to carry out this experimental prototype both in Argentina and in the rest of the countries. of the world.

If you are interested in this project you can contact me at email:

Martín-Giordano@hotmail.com.