Renewable Energy in Future Water-Based Sport

The combination of climate change, the growing need to convert to renewable energy and new technical developments in watercraft provides the basis to develop new forms of water-based competition.

Introduction

The history of athletic competition dates back to Ancient Greece. Competitive wind-powered sailing dates back to the late 1600’s with competitive rowing dating back to the same time period. Over the centuries and decades, the technology of both oar driven and wind driven boat propulsion has advanced. Modern wind-powered competition boats include multiple narrow hulls to reduce water drag, with wing-like hydrofoils allowing the boat hull to lift above water as vessel speed increases. Some modern wave-propelled surfboards include small-scale versions of the same wing-like hydrofoils on the underside to allow the board to ride above the water surface.

Several surfing enthusiasts have combined airborne kite propulsion with hydrofoil surfboards to develop a recreational watercraft capable of traveling smoothly above choppy water at elevated speed. 

While surfboards are the traditional wave powered watercraft, there has been technical development to develop wave-driven watercraft capable to sailing directly into waves. While hydrofoil surfboards were originally developed for easier sailing through choppy water, the development had a spin-off that allows the rider to achieve forward propulsion by rocking the foil-surfboard to produce a pitching motion and perhaps forming the basis of a future human-powered competition watercraft.

Competitive Wave Power

Many inventors internationally have developed various configurations of wave-powered boats. By mid-July 2008, Japanese sailor Kenichi Horie successfully sailed a wave-powered boat across the Pacific, from Hawaii to Japan. 

The main problem with trans-ocean wave powered sailing is that mid-ocean waves typically have extreme wavelengths while omni-directional wave-powered boats sail optimally through choppy water with short wavelengths, as occurs offshore near coastal areas and in windswept enclosed bodies of water. These types of waves are very different to the waves that are optimal for ocean surfing, allowing for wave powered boats to sail at very different locations to surfboards.

Regions where wind-driven choppy water occurs frequently could represent future locations for competitive wave-powered watercraft. If the sponsorship world were willing to offer a prize, such competition could attract entrepreneurial and inventive types of people interested in developing ingenious ways of converting wave energy to vessel propulsion. The prize could encourage development of vessels capable of exceeding a speed of six knots and ride up on hydrofoils. Future sponsored competition could involve races among groups of wave-powered hydrofoil boats at locations were local winds would generate choppy water on the surface of enclosed bodies of water.

Port Area Tour Boats

Entrepreneurs seeking to attract environmentally conscious tourists could explore business opportunities using wave powered boats to ferry visitors around areas of ports and enclosed bodies of water where wind-driven choppy water occurs. In many locations internationally, port area tour boats sail at very low speed that during periods of choppy water, could convert wave energy to low-speed propulsion. The difference in temperature between land and sea results in daytime coastal winds that move air from the sea toward land, producing choppy coastal water in many locations to sustain daytime operation of wave-powered boats.
 
Kite Propulsion

While kites are being used to assist ship propulsion and also to pull a small number of comparatively small tourist cruise vessels, surfboard enthusiasts represent by far the most widespread use of kites for watercraft propulsion. There is scope for future kite-propelled watercraft to involve multi-hull design with hydrofoils to allow for fast sailing through choppy water. Wind speed increases with elevation with a kite at 300-meter elevation encountering winds blowing at 50 to 100 percent greater speed than winds that push on sails, producing 2.25 to four times the propulsive force per unit of area. 

Sailing from west to east, a high-elevation kite would require nighttime illumination to alert aircraft of its presence while pulling a boat. Depending on kite elevation and wind speed at that elevation, it may become possible for high-elevation kites to pull a vessel at sufficient speed to allow it to become airborne on specially designed ground-effect wings. There may be future possibility for trans-ocean races involving wing-in-ground effect vehicles being pulled by high-elevation kites and traveling in the direction parallel to trade winds. Such a competition could come to fruition courtesy of corporate sponsorship. 

Kite Surfboard Racing

Kite surfboard racing where competitors use kites to tow surfboards and hydrofoil surfboards at numerous ocean and inland waterway locations has already evolved into a competitive sport that attracts large numbers of competitors. Future innovations in design of kites and design of surfboards would likely raise speed and improve board stability in choppy water conditions. Enthusiasts have already set local records sailing between islands and sailing across bodies of water. The trend is likely to continue as some enthusiasts seek to establish distance and speed records, including sailing through extreme conditions.

Pumping Hydrofoil Surfboard Racing

The addition of wing-type hydrofoils under surfboard achieves multiple results that include lifting the board above water to increase speed while simultaneously improving stability in choppy water. Perhaps the unexpected result was the rider being able to rock the board in a pitching motion to achieve forward propulsion. Away from the ocean coast in bodies of water with minimal wave action, towing the rider and board or generating an artificial single wave initiates sufficient forward movement at sufficient speed to lift the board on to its hydrofoil wings to allow the rider to pump the board.

For inland waterways and lakes, there may be scope to investigate methods by which to enhance forward movement through board pumping. One possibility would be to investigate the installation of a whale-like tail fluke behind the rear hydrofoil and whether such a fluke would assist pumping-activated forward propulsion. In competition, a single artificially generated wave would get the competitors started and lift the boards on to their hydrofoils before the competitors pump their boards as they race against each other. Hydrofoil surfboard racing on enclosed bodies of water could become a future competitive water sport.

Pedal Propulsion

Various configurations of pedal powered watercraft have existed for decades, the most popular being two-passenger rental boats on pontoons and where the pedal cranks directly drive a paddle wheel. In 2007, Canadian adventurer Greg Kolodziejzyk built a pedal-powered, ocean capable enclosed kayak intended to undertake long-distance travel. Pedal-powered kayaks are sold commercially while bicycle-trimaran hybrids, some that include hydrofoils are being built and marketed for competition enthusiasts. Racing and endurance competitions involving pedal-propelled watercraft have occurred on ponds and rivers in several countries. More innovative designs of pedal-propelled watercraft are likely to appear in the future.

On June 12, 1979, a pedal powered aircraft called Gossamer Albatross crossed the English Channel. That precedent provides the basis for developing a pedal-powered wing-in-ground effect craft that a rider or riders could accelerate from a coastal road and seek to establish a distance record for airborne pedal-powered vehicles traveling across a channel that is wider than the English Channel. To lift off from a water surface, the craft would require a lightweight planetary-geared flywheel that pedal power would accelerate to high rotational speed before engaging a variable-pitch propeller to accelerate the vehicle to elevation speed.

Solar PV Propulsion

The steady decline in solar PV technology has seen development in solar rechargeable boats and low-speed watercraft that operate solely on solar PV energy for daytime propulsion. Solar PV power assisted by ultra-capacitor storage technology can accelerate a watercraft to ride up on to hydrofoil. Future improvements in solar PV technology could find application in future races involving competition solar PV powered watercraft. On future application for advancing solar PV technology would be on a wing-in-ground effect vehicle that could accelerate along a coastal runway to become airborne then travel for extended distance above water.
 
A solar PV powered ground-effect vehicle could include solar-electric recharged ultra-capacitor technology to help accelerate the vehicle to elevation speed from a water surface. Unlike solar powered aircraft that feature extreme wingspan dimension, solar powered vehicles could be built to extreme length and with comparatively narrow wingspan and extreme wing chord dimension. The development of such a vehicle would initially require sponsorship and could represent a possible advertising and product promotional opportunity for manufacturers of solar PV technology. There could also evolve commercial applications for solar PV powered ground effect vehicles.

Conclusions

Advances in technology are gradually making non-traditional renewable energy propelled watercraft more practical, more cost competitive and more attractive for recreational users, competition enthusiasts and commercial customers. There may be future market applications for wave-powered watercraft, solar PV powered ground effect vehicles, kite powered racing boats and competition oriented pumping surfboards that feature a whale-like fluke attachment to raise speed.