University teams from across Europe battled it out to become the underwater robot champions at one of the world's largest freshwater tanks that is normally used by the UK's defence department for ship and submarine trials.

The winners for the second year in succession was a team from Heriot-Watt University in Edinburgh, Scotland, who triumphed over their international competitors at the fourth Student Autonomous Underwater Competition - Europe, held at the QinetiQ Ocean Basin, in Gosport on southern England's coast.

The Heriot-Watt team designed and built a hover-capable autonomous underwater vehicle (AUV) able to carry out a complex in-water mission with no direct human control.

The team of students worked hard to ensure that the AUV completed the mission successfully. The work paid off, with their "Nessie" AUV taking first place, demonstrating high autonomy and capabilities beyond any of the seven competitors, coming from different European universities.

The tasks successfully completed by Nessie 6 include tracking of a moving mid-water target, hovering closely above an identified ground target, wall following with sonar, and a very tough underwater docking task.

Team captain Francesco Maurelli said: "It was a real honour to lead this team, full of energy and enthusiasm. Every single person has put a lot of effort into the vehicle and it was great to see the results of that. I would like to thank our sponsors BP and PNI Corporation for their generous contributions.

"This victory would not have been possible without their help. We are also grateful for the efforts of the previous year's teams from Heriot-Watt, on whose work we were building," he added.

Professor Yvan Petillot, academic supervisor of the team at the university's Ocean Systems Laboratory, said: "Among stiff competition, what made the difference was the professionalism and quality of the team. I feel privileged to have been part of this adventure."

The sponsors in this project have followed its progress closely. Angus Hinks from BP congratulated the 2009 team and said: "We have watched with great interest the development of the Nessie vehicle over recent years. BP understands the advantages of using AUV technology and continues to support development and deployment programmes."

The Student Autonomous Underwater Challenge - Europe (SAUC-E) 2009, coordinated by the Defence Science & Technology Laboratory, puts the future generation of engineers, mathematicians and scientists to the test by tasking them to design and build an autonomous underwater vehicle.

SAUC-E was created not only to advance AUV technology but to help foster ties between students and organisations involved in AUV technology. SAUC-E organiser Phil Brown said of the event: "The competition is a brilliant way for students to gain some ‘hands-on' systems engineering experience, to generate novel ideas for AUV development and to make contact with others who work in this specialist area."

The AUVs need to be of a highly sophisticated level in order to perform a series of realistic underwater missions with no control, guidance, no communication from a person, or from any off-board computer including GPS systems, in a challenging underwater environment. Eight university teams from the UK, Germany and France competed for this year's title.

The Defence Science & Technology Laboratory is a centre of scientific excellence for the Ministry of Defence. Its 3,500 workforce includes some of the nation's most talented and creative scientists with the brief to ensure that the UK armed forces and government are supported in-house by the very best impartial scientific and technological advice.

QinetiQ is a leading international defence and security technology company with 8,000 employees in Europe, the Middle East and Australasia and more than 5,500 in North America. Its Ocean Basin at Gosport is Europe's largest freshwater tank and is regularly used for trials to assess the manoeuvrability of scale ship and submarine models in different sea conditions.