The 1km swim, which took place at Hobie Beach, provided a platform for Masakhane Future Stars development swimmers to compete in an open-water event while rubbing shoulders with the best in the business, said watersports coordinator Michael Zoetmulder.
Slovenian champion Kerin (27) was first out of the water in 13:43, followed by Gauteng's former national three-kilometre champion Abdul Malick Railoun (18) in 14:24. The latter pipped PE's Chris van de Sande (18) by four seconds.
Marathon swimmer Kerin said he found the shorter race even tougher than the previous day's eight-kilometre event.
"I'm not used to going so fast from the start," said Kerin.
After lying third at the outset, he fought his way into the lead and then opened up a commanding gap from the first buoy.
Capetonian Dryding (18) finished the women's race in 14:57, almost a minute ahead of local challengers Jessica Roux (18), who recorded a time of 15:59, and Tarryn Els (14), third in 17:24.
Dryding said she felt a little tired as conditions had been slightly choppy but that is was better.
"Compared to yesterday (Saturday), anything would seem perfect," said Dryding.
There were also trophies and cash prizes for the top three swimmers in the development category.
Mkhululi Heka (16) took the honours in 24:32, with 15-year-olds Xhanti Fulani and Qhamani Moni completing the podium in 26:09 and 26:29 respectively.
With the Bay's municipal swimming pools closed due to water restrictions, the teenager said he had only been able to prepare for the event with regular sessions on the stationary bike and treadmill in the gym.
According to Kerin, the festival provided a great opportunity to promote the sport of open-water swimming through the various events.
"It’s always better to have more than one race and the shorter swims take place closer to shore, so it’s good for spectators too."
He said he had also signed up for Monday's crowd-pleasing King of the Bay elimination swim.