The future could be fake
On long, hot summer days when the northerly is blowing and the ocean is as flat as a tack, surfers itch for a wave to help pass their day. The search for perfect wave drives most surfers to remote beaches along the coastline or treacherous offshore outer reefs, but when there is no swell on the horizon, only dreams of surfing eventuate. Greg Webber has turned his flat spell dreams into invention, coming up with a unique concept for a circular wave-pool to provide surf on demand.
It is every surfer’s dream: catching the perfect wave, bottom turning and stalling into the pristine greenroom where the lip continually curls overhead, on and on in an endless barrel. Greg Webber, a world-renowned surfboard shaper that started in coastal engineering, knows where to find such waves. He has even caught them on film.
Unfortunately, no-one could ride these perfect waves as they were only a few centimetres tall – an effect created by an ordinary fishing boat chugging down the Clarence River in NSW, Australia, and caught on film by Webber’s brother Monty, a surf film maker, by walking along a sandbank with a lipstick-camera and filming in slow motion. The pair subsequently made the film Liquid Time and presented it to the surfing world where it received great reviews and an international film award. While standing on this sandbank, Greg Webber pondered how to capture these waves – increase their size and ride them. He wondered if a large moving hull could be used to generate waves capable of being surfed, especially if the hull was running alongside a channel, thereby making a wave pool.
Floating wave generators
Trying to catch waves generated by large ships, fast ferries or tankers is nothing new. Surfers in environments as diverse as Vancouver and the Netherlands are surfi ng the somewhat dangerous places where ship wakes hit the shore and break. On Vancouver Island in Canada, surfers nicknamed the Pacifi Cat Ferry the “two-hundredmillion- dollar wave generator”. Each time the ferry passes, at least 30 or more waves are formed. Several of them are very rideable and some even form the desired barrel shapes.
The most extreme ship-wake surfers are probably those in the Netherlands. Surfing the polluted and rubbish-ridden River de Waal where they battle sewage, general river pollution and the risk of being run over by the same ships that created their waves.
These examples show that wake surfing is feasible, but only if the wake is large enough, the bottom contours of the river bank have the right shape and the tide is correct. So, Webber decided to do his own experiments. Using a fishing trawler of similar size to his theorised hull design, waves capable of being ridden were generated up to chest high. Furthermore, even in the imperfect conditions of a river, barrels could be produced.
The test was a success and, with a faster boat, even bigger waves could have been generated. The experiments also showed the importance of another effect.
Dart Island, the test site within the Clarence River, experiences a focused high velocity tidal fl ow along the western edge, which results in a semi-circular beach section with a stable slope angle which graduated from 1 in 15 to between 1 in 12 to 1 in 8. It was on this semi-circular piece of sand where, not only was the concept of the full circular island conceived, but also the critical nature of the current realised.
Attempts at making wake in the same direction as the current were dismal failures, while passes against the tidal fl ow created tightly packed, steep-faced waves that would break very aggressively. Also, by further experimenting with the boat path, it was realised that a curved approach further compressed the wake waves, steepening the face at the outer edges, where it would otherwise be weakening.
The vision of the circular wave pool was generated, however many waves going around a central island in the same direction would induce a current, a dangerous conundrum. So, an important component of Webber’s design needed to include a counter current in the pool to offset the effect of the waves. As the river tests showed, this would also act as an improvement to the design because a reverse current would stand the waves up even more and make them break with even more power.
Wave pools are nothing new. In 1934, the Wembley Swimming Pool in London was the first to thrill its visitors with small artificial waves. In 1966, the first indoor surfers rode waist-high waves in the Summerland wave pool in Tokyo, Japan. Since then, some special surf pools have been built around the world, receiving somewhat mixed reviews from surfers. The original linear moving wave pools try to mimic natural waves with piston-driven paddles or similar mechanical devices. Such man-made waves are not very appealing to surfers although some manufacturers are now bending the pool around a curve to concentrate the swell or model the pool floor to improve the wave height.
Much larger waves are created by standing wave surf pools which push water over a fixed wall curved like a large wave. Behaving more like a water-powered half-pipe than a wave, such pools do not provide a very authentic riding experience and, like the linear pools, allow only one rider at a time.
A third concept moves a central hull along a linear track creating two waves on each side. WaveLoch is developing such a wave, calling it a “moving reef ”. It is a hull generated system similar to Liquid Time, however the major difference is that it is linear and operates in shallow water, with two wave per hull either side of a central track.
Video: Ocean Dome Wavepool in Japan
footage courtesy of ASL's 'Typhoon Wasabi & the Kamikaze Kids' DVD, 2007. www.surfinglife.com.au
The Webber concept
In contrast, Webber’s circular Liquid Time Wave Pool is capable of providing a theoretically infinitely long ride around a central island. The waves are created by the wakes of a series of hulls driven around the outside of the pool. The pool will be capable of creating waves from beginner to expert level, with a wave face up to 2m high.
The standard configuration is a pool with an outer diameter of 200m, and an island of 132m diameter at its centre. The pool has fi ve hulls circling on the outside. This design offers ten waves which continually break, with a single ride around the island lasting over 2min.
The fibre-glass hulls will be guided and driven by standard roller coaster tracks and drive systems located in the outer wall of the pool. Nozzles on the pool floor will be used for water filtration, chlorination and heating, while also providing the important current, counteracting the flow induced by the rotating hulls. The necessary velocity of the counter-current is as low as 1m/s and can be further reduced by deepening the pool. As unique as the concept of the circular surf-pool is, it relies almost exclusively on techniques and components well proven in the theme-park or swimming pool industries.
The pool is designed to produce both left and right hand waves simply by changing the directions of the hulls and counter-current, as well as changing the size and shape of the waves by varying the speed of the hulls and counter-current. The operator would then run a timetable of waves, for example expert rights from 0600-0700 for the before work crowd, intermediate rights from 0700-0900 for the before schoolies, and from 0900-1000 beginner lefts for the mums and visitors.
Using the described set-up, with two waves breaking off each hull, ten surfers could be riding at a time. With each surfer getting a standard 30s ride (quarter of the wave around the island) and with one wave every 5min, up to 100 surfers can ride in each 5min surf session.This also means each surfer can get twelve 30s waves (even barrels) per hour. While the average ride length in the usual beach break conditions is about 10s, the circular pool’s 30s rides will challenge the strength of even the fittest surfers.
Another plus is the alignment of wave and shoreline. Waves break perfectly along the edge of the circular island. This is an exciting prospect for competent and expert surfers.
More importantly, however, this alignment affords an opportunity for beginners to learn to ride waves with consistent speed, power and slope of face. A total beginner can catch the whitewash and then cut towards the shoulder. In one quick movement, beginners will be on the face of the wave, where they can ride on their belly, then get to their knees and fi nally to their feet.
The advantages of the concept are striking: a safe learning environment as well as a challenge for expert surfers, multiple surfers at a time and long-lasting large waves. A circular surf-pool has the potential to fi nally bring an authentic surf experience to everyone, no matter how far away from the coast they live.
More than just a theme park possibility, the pool has been identifi ed more for the fi tness market. With the fi tness market, people would be inclined to use the pool on a daily basis, or even twice daily with before and after work surfs, while a theme park would be a once or twice a year visit.
Unfortunately, it’s still a concept. Webber has established a company – Liquid Time Pty Ltd – which owns the patents for the wave pool and the fi rst Memorandum of Understanding with a client has been signed.
Friends and partners from industries as diverse as theme park building and computer modelling are contributing to the design. Liquid Time has also teamed with Michael Lee Design (MLD), a leading Theme and Water park design and construction company in the US, to provide additional expertise in the pool design. Computational Fluid Dynamic modelling, scale model testing of different hull shapes and the importance of water depth has been tested at the Technical University of Delft confi rming the original design’s feasibility and providing improvements.
A 1:10 scale model test of the complete set-up is currently in the planning. Liquid Time has also produced a full three dimensional representation in 3D Studio Max to illustrate a possible indoor surfi ng facility.
Video: Liquid Time Wave Pool simulation
Property developers are now conceiving the idea of surf-based estates, with a wave pool replacing the traditional golf course as its centrepiece. Liquid Time has been developing the commercial viability of surf-based estates with River Island Property Developments, with the first pool proposed to be built in the Hunter Valley in NSW.
So, it may still be some time before waves go in circles. But one day Greg Webber will succeed in catching the perfect wave and then he’ll bring them to everyone.
By Steven Schmeid
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