The "beauty" of Lake Dunstan is the seemingly endless beaches, lake harbourmaster Shayne Hitchcock says.
Unlike in other popular boating areas in the district such as Wanaka and Queenstown, that means people can spread out around Lake Dunstan, preventing congestion.
However, when the wind picks up, people tend to converge on sheltered areas such as Old Cromwell.
For that reason, Mr Hitchcock has installed a new set of marker buoys in the area for the holiday season.
But, despite the signs clearly reminding people to "keep right" in accordance with international law, Mr Hitchcock says he still has to remind people of the rules.
He also has to remind them not to take their motorboats inside the designated swimming areas, and to stick to the speed limits.
"It's amazing the excuses people come up with," he said.
There are seven such swimming areas around the lake, all roped off and marked with buoys in the water and signs on the shore.
Boats are not to travel faster than five knots, which is likened to a fast walking pace or a speed that does not create a wake, within 50m of swimmers or other boats, within 100m of shore and within 200m of any boat displaying a blue and white divers flag.
Despite having to remind people of these things, in his 15 years as harbourmaster, he said he had not imposed any fines.
He said his role was one of education and enforcement and if he gave out fines, he would not be doing the education part of his role properly.
He could not say how many boats had been on the lake during the holiday period, but he said he had given out more than 150 information packs.
Despite the short-lived but frequent rain showers yesterday afternoon, there were plenty of people on the lake.
All those the Otago Daily Times spoke to seemed to be repeat visitors; one man had been holidaying there for 40 years.
They all had high praise for the lake, for most other users, for Mr Hitchcock and even for Land Information New Zealand for clearing weeds such as lagarosiphon.
However, with so many people on the water, frustrations had arisen and the most common cause seemed to be jet-skiers.
Barb and Mike Sowman, of Dunedin, said some jet-skiers had come in close to where they were with their children and done "donuts".
Mr Sowman also said some people could not keep right in the gorge, "but having the harbour guy really helps".
Staying safe on the lake
- There are seven designated swimming areas around the lake.
- All are roped off and signposted with buoys in the water and signs on the shore.
- Boats are not to travel faster than five knots, which is likened to a fast walking pace or a speed that does not create a wake, within 50m of swimmers or other boats, within 100m of shore and within 200m of any boat displaying a blue and white divers flag.
- Power boats are to give way to others on their starboard (right) side as well as vessels under sail such as sailboards and yachts.
- People must be 15 or older to be in control of a power boat.
- Every vessel, including jet skis, must have a "spotter" if it is towing.
- Spotters must be 10 or older.
- Lake Dunstan extends from the Clyde dam up to the Bendigo wildlife area and out to Bannockburn.