SeaCat AUV Inspects Water Supply Tunnel
Operating Remotely and Autonomously, SeaCat Surveys And Records Video of 24-Kilometer-Long Tunnel
By Jörg Kalwa System Engineer Atlas Elektronik Bremen, Germany
n a mission lasting almost seven hours, the SeaCat AUV, made by Atlas Elek- tronik (Bremen, Germany), dove through a water supply tunnel 24 kilometers long in the vicinity of Stuttgart, Germany, success- fully investigating the tube for damage. With this survey in March 2012, it be- came possible to inspect the Albstollen water-supply tunnel in the state of Baden- Württemberg for the first time in 40 years of operation.
First Visual Inspection of the Tunnel The Albstollen tunnel, with a length of 24 kilometers and a
diameter of 2.25 meters, forms part of the water-supply system operated by Bodensee-Wasserversorgung (Stuttgart). As the largest German long-distance water distribution system, it pro- vides freshwater from Lake Constance to 4 million people in 320 communities. One of two main lines, the Albstollen passes through the Swabian Jura mountain range to sup- ply Stuttgart and the northern part of Baden-Württemberg. Although the concrete duct had been checked regularly in the course of its more than 40-year lifetime through measurements of the hydraulic friction losses and the leakage rate, a visual inspection of its condition over the entire length had not been technically possible until now. To inspect the water tunnel, Atlas Elektronik deployed an autonomous diving robot.
Operating Autonomously or Remotely The SeaCat AUV, which measures 2.5 meters in length and 30 centimeters in diameter, was selected for the project due to its size and ability to operate either remotely controlled or autonomously, with an endurance of eight hours and a range of 40 kilometers. Video cameras and a variety of sonars can be carried as the payload sensors. Typical areas of appli- cation include the inspection and mapping of inshore lakes, coastal sea areas, harbors and marine structures such as dams or the foundations of wind turbines.
(Top) The SeaCat AUV on a chain during deployment to the Albstollen tunnel.
(Middle) The SeaCat AUV emerges from the Albstollen tunnel in a shaft surge chamber.
(Bottom) The team recovers the SeaCat AUV from the mission. www.sea-technology.com AUGUST 2012 / st 43