The River Cam has long been known for its 'punting' boat trips - but rising hostilities are threatening to spoil the idyllic reputation of the famous waterways.
Staff monitoring the Cam are to be issued with stab vests, amid increased tensions between punt operators vying for business.
The Cam Conservators, the statutory navigation authority for Cambridge, have taken the extreme measures due to the 'increase in hostility being displayed towards staff while patrolling the riverbanks'.
The usually relaxed atmosphere along the banks of the Cam has been disturbed in recent years by heavy congestion among punts, sunken boats and squabbling between rival punt operators.
Rowers have also been caught urinating in public and boats have been deliberately released from moorings in the latest spate of trouble.
Staff at the Cam Conversators demanded stab vests at their latest meeting.
A report issued by the group said: 'The river bailiff has asked to be issued with a 'stab' vest given the increase in hostility being displayed towards staff while patrolling the riverbanks.'
The meeting was also told: 'A live-aboard boater complained a rowing eight came close to their vessel and one of the crew members stood up and urinated openly in front of them at breakfast time.
'The live-aboard owner tooted the boat horn at them in objection.
'The crew found this very amusing.'
Kevin Price, a Cambridge city councillor and member of the Conservators, added: 'It was felt that, in terms of a duty of care to staff and to protect them, it was better to be safe than sorry.
'It's a sign of a sad time when we have got to think about providing such equipment for a guy who is just doing a job.'
River managers say motorised boat owners, who have a 'bloody-minded attitude' toward rowers, have fueled tension with traditional punt operators.
Dr Pippa Noon, the river manager, said: 'A certain minority of powered craft owners take a bloody-minded attitude towards rowers, either failing to give way to them or not reducing their speed or wash when passing.'