The technology behind RIF010: No wave too high

In ten years, Rif010 was realized in the heart of Rotterdam. The world's first urban surfpool where both novice and advanced surfers can show off their skills to crowds of passers-by on artificially generated waves. The technical heart of these waves is located in a separate space under a terrace and includes eight wave chambers that can generate different waves. For this purpose, eight large blowers with a motor power of 132 kW are used to generate up to 350,000 cubic meters of air per hour. Controlling the valves to reverse the air is done with servo motors and controllers from Festo.

The plans for RiF010 were put on the table as early as 2013 by Edwin van Viegen. He worked them out as part of a competition in which Rotterdam asked for ideas to liven up this particular part of the city. The avid wave surfer envisioned realizing a serious surf pool in one of the canals - into which the water from the river Rotte flows. The technology for generating artificial waves was known from wave pools and was being further developed at the time by one of his connections.

Surfing, supping and a beach

With the winning of the competition, financial resources also became available. Finally, the challenging project was completed in 2024 with the opening of Rif010. It has become a real attraction where people can surf and - beyond the surf pool - also supp, bodyboard, canoe and even dive. The surfers surf from the place where the waves are generated to a concrete beach. Next to this beach, on the quay, is the beach house. Here the water sports enthusiasts can change and shower, and catering facilities are available. Of course, also for interested people.

The technical room to realize the waves is located under a terrace. In it there is an impressive technical installation developed entirely by the Hellebrekers company. Erik Keyl is company manager of realization and comments: "It has become a special project in which attention was not only paid to the realization of waves from 1 to a maximum of 1.6 meters, but also to energy consumption and the limitation of possible nuisance for the surroundings.

Wave Generation

The technology room is set up to create different waves in eight wave rooms. The 1-meter high waves are intended for beginning surfers, the 1.5-meter variants for the more advanced to the up to 1.6-meter high waves for "experts. In the latter case, the wave also breaks hollow and is steeper.

The waves are created with air generated by a blower system designed and built in-house by Hellebrekers. The eight large frequency-controlled blowers, each with a 132 kW electric motor, bring the air to the wave chambers. Each electric motor is equipped with its own frequency controller which is necessary to create the waves of different heights. At the surf pole "at rest," the frequency is around 30 Hz. At the 1 meter wave it rises to 36 Hz and at the maximum wave height to 50 Hz. Three large silencers prevent the sounds of this installation from causing nuisance to nearby residents.

The actual forming of the wave occurs in the wave chambers in a cycle of about 7 seconds - a time span typical of wave motion in the North Sea. In the process, air is first drawn out of each wave chamber for 5 seconds, creating a negative pressure. After this, the electrically controlled valves switch the direction of the air flow and the lifted air is pushed out in about two to three seconds. In combination with the bottom structure of the surf pool, the reef, the desired wave is built up. This occurs over a width of about 23 meters. After the generation of a number of waves, the wave generator stands still to bring the surf pool to rest. An undercurrent is then also created where the water flows back toward the wave chambers and takes the surfers back to their starting point.

Switching the valves

The valves used to reverse the direction of airflow are driven by EMMT servo motors of Festo; control is via a CMMT controller. The reason for choosing precisely these servomotors is related to the available torque. In addition, precisely this combination of servomotor and controller is ideal for achieving the correct timing required for valve switching.

The software uses a so-called digital camshaft for this purpose. This is similar to a mechanical camshaft that controls the position of a valve in time and thus the speed at which this position changes. The great advantage of a digital camshaft is, of course, the fact that the cams do not have to be adjusted mechanically every time they are not yet optimal, but this is easily possible by changing the setting in the software.

The collaboration between Festo and Hellebrekers went extremely well. As a result, the two companies regularly work together on various and challenging projects. Erik Keyl: "I need Festo not so much to tell; here is the knowledge and insight that allows people to quickly understand exactly what we as Hellebrekers need. That means that this drive and control combination was seamlessly integrated into our own system controlled by a Siemens controller. The support in the final commissioning was also pleasant and welcome. Another great project completed."

Under the terrace of the beach house is the treatment plant also designed and built by Hellebrekers. This plant continuously filters the water from the surf pool for solids through the 60 µm filter of the drum filter (blue). Also, new water entering from the Rotte River is first pumped to the drum filter by two circulation pumps of 7.5 kW each. At the request of the Water Board, the surf pool is available at high water to temporarily buffer water. There is a separate filling pump for this purpose and a separate setting on the control box. When this condition arises, excess water is let in until the level of the pool is raised a maximum of 60 cm.