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• 1 Introduction
• 2 Hull design approach
• 3 Results
• 4 Discussion & References

3 Results 

By deriving the available power supply by a human from Figure 2.9, and transferring this towards the hull energy presented in Figure 2.12, the instantaneous speed can be determined for each hull type. By integrating the speed over time, the distance being passed can be calculated. Figure 3.1 shows the required time to sail distances beyond 10 kilometres. Figure 3.2 gives an indication of the energy consumption in relation to the distance.
Again the figures are shown for a short distance scale up-to 100 metres, referring to Figure 3.3 and Figure 3.4.

The figures that are presented show ideal estimates of waterbike performances and energy consumptions. In practice, a considerable amount of energy is lost when transferring human power into ship speed. Elements that introduce energy loss/consumption are:

• Additional water resistance of appendages such as rudders and propulsion shafts;
• Additional wave resistance due to undesired longitudinal trim of the hulls;
• Mechanical losses of the shafts, chains and gears of the propulsion unit;
• Propeller / peddle wheel losses;
• Air and wave resistance due to weather conditions on channels and lakes;
• Take-off energy to get airborne in case of hydrofoils
• Stabilizer losses in case of active stability control of unstable waterbikes and hydrofoils

Therefore the results being presented are only useful for a comparison purpose between different hull type performances related to the human power supply.
Efficiency losses can vary significantly between different waterbike propulsion designs and their manufacturing.

Figure 3.1 Elapsed time versus long distance (beyond 10km) for different hull types

Figure 3.2 Energy consumption versus long distances (beyond 10km) for different hull types

Figure 3.3 Elapsed time versus short distances (100m) for different hull types

Figure 3.4 Energy consumption versus short distances (100m) for different hull types

When comparing the different hull types in relation to their long distance and short distance performance, the following conclusions can be made:

• Long distance performance.
  In case of a long distance sailing of 10 kilometres, the best performing hull types are slender mono-hulls and catamarans. Hydrofoils show less good performance because they cannot manage to continue flying. Being afloat, they have to cope with hull resistance and wing resistance. Planing hulls perform poor due to the fact that they are not planing and because they have a large wave resistance in comparison to the other hull types.
• Short distance performance.
  In case of a short distance race of 100 metres, hydrofoils are the most fast. Their hull is lifted out of the water and the wing underwater makes it possible to sail efficiently at high speeds. With this comparison it is assumed that the hydrofoil is already airborne before start. In case of starting at zero-speed, the performance in terms of time becomes less. The amount of energy required increases slightly.
  Planing hulls can be fast, if enough power is supplied and planing mode is guaranteed for the whole distance. Figure 3.3and Figure 3.4 show the curves for a planing mode with well-trained males pushing the pedals. After 70 metres the required time to overlap distance increase drastically. Also the required energy increases at the same moment. In planing mode, the required energy is about equal to slender mono-hulls and catamarans. In case of not planing, the required total energy consumption is larger. Well-trained males consume even more energy than good trained males due to the fact that the well tained mails sail with a speed closer to the resistance hump.

Also it can be concluded that the performance of catamarans and slender mono-hulls is about similar. Figure 3.5 shows an exciting competition between slender mono-hull Macbath from Delft Waterbike Technology and catamaran l'Ordegno from Triëste Waterbike Team, at the International Waterbike Regatta 2002 in Genoa, Italy.

Figure 3.5 Competition between slender mono-hull Macbath (close) and catamaran l'Ordegno (far)

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