“Sometimes the jellyfish are so thick that you can’t even see right in front of you,” Silvester (34) said.
“But I don’t get nervous, I am always just excited.
“Each time I try and beat my personal best time if I can. With any competition, ocean or pool, it is just a matter of getting in there and getting past that finish line.
“That’s the main thing.”
Event host Claremont Masters Swimming Club will donate part-proceeds from Swim Thru Perth to the WA Disabled Sports Association.
After joining Superfins WA at age six, Silvester, who has cerebral palsy hemiplegia, is the longest competitive member of the club.
“I’ve been swimming since I was little, basically since I was born,” he said. “When I was about nine, I started competitions and I thought, ‘oh I love this’.
“It’s about feeling strong, getting fit, socialising with your clubmates and meeting new friends from different swimming clubs.”
Black, who has an intellectual disability, won the Masters Swimming Australia male age group open water award in 2013 and 2015.
The 26-year-old said he was training at least three days a week to prepare for the swim.
“My first time was in 2008 and I came out muddy, but since then the river has gotten cleaner,” he said. “I think 2010 was the toughest year I’ve ever competed because the weather picked up and it got rougher and rougher.”
Competing in a duo this year will be Silvester’s 10th Swim Thru Perth crossing.
“When its really rough conditions, some of the organisers let me finish the swim regardless of the cut-off time,” he said.
“Afterwards, I think I’ll celebrate with my mates and a couple of beers as well.”