More than 270 entries were submitted for a competition designed to help prevent vandalism of life-saving equipment along the River Nene.
The competition was launched as part of a drowning prevention project by East Northamptonshire Council, the Environment Agency and Northamptonshire County Council.
The challenge was for under-18s to design a message or picture which will make a vandal or thief think twice before messing with lifebelts at locks and weirs.
This equipment costs thousands of pounds and theft or vandalism of it puts lives in danger.
A panel of judges including council chairman Gill Mercer, schools swimming manager at Northamptonshire County Council Steve Jackson, Nene and Lincolnshire Waterways manager at the Environment Agency Sue Cant, and Sector Commander at Northamptonshire Police Insp Inam Khan, had the task of selecting six winners who will have their design published and used in the centre of lifebelts available along the River Nene in East Northamptonshire.
Each winner will also receive an Amazon voucher.
Cllr Gill Mercer said: “It was very difficult to choose from so many excellent designs.
“There were some very good strong messages even from the ones that didn’t win.”
Insp Khan added: “Schools should be commended for the high quality of designs and the effort that has been put in.”
Sue Cant said: “We’re really pleased to see such a high standard and variety of designs. The winning ones will be displayed at lock sites where people will see them and take notice of the messages. Well done to all of those who took part.”
The chosen designs will be put on the lifebelt holders on June 19 ahead of National Drowning Prevention Week. For details go to www.drowningpreventionweek.org.uk.