The Derwent River Big Swim is a 34 km swim down the River Derwent, starting at Norfolk Bridge and finishing at the Tasman Bridge in Hobart, Tasmania. The water temperature hovers around 16 degrees in December, when I swam it. The swim adheres to traditional ultramarathon rules, meaning it’s completed in bathers only. With an outgoing tide providing assistance from the 16 km mark, the river’s freshwater offers less buoyancy but also reduces chafing.
For those new to ultramarathon swimming, the English Channel—a 34 km stretch from England to France—is the most famous challenge. Ultramarathon swimming has its own global community, featuring athletes of various speeds tackling long distances in oceans, lakes, and rivers to push their limits. To make these swims official, they must be observed and logged, with swimmers wearing only bathers. While wetsuit swims are still recognised, they don’t meet official criteria.
In a past life as an athlete, I raced 10 km marathon swims professionally for Australia, competing in World Cups and World Championship events, as well as 5 km and 25 km open water races. In late 2018, I returned to serious swimming after a break, training for the 2019 Rottnest Channel Swim—a 19.6 km swim to Rottnest Island from Perth (Western Australia). My goal was to win, and I’m proud to say I achieved that.
Fast forward to late 2024, nearly six years since my last long swim. Life looks very different now; I’m a dad, juggling two jobs, including running this wetsuit business. My preparation for the Derwent swim wasn’t ideal, averaging less than 20 km a week in the pool, and falling ill in the week prior added to the challenges. But this swim wasn’t about breaking records; it was about enjoyment. Thankfully, my body, conditioned from years of training, knew what to do.
I made the short trip from Melbourne, flying into Hobart the night before and staying on my skipper Val’s large catamaran, moored at the bottom of the Derwent River. Keeping things simple, I carbo-loaded with pizza. The next morning, I woke at 5:00 am, ready for the 7:00 am start at Norfolk Bridge. My parents joined me on the boat, assisting with feeding. My dad, at 65, was preparing to swim the same course a few days later as part of his own adventure.
Every swimmer has their feeding strategy, and I’m fortunate to have a stomach that can handle almost anything. My plan was to consume 80g of carbohydrates per hour in liquid form, using Maurten drink mix 320 from Aid Station, which also includes electrolytes. Dehydration wasn’t a concern given the cool water temperature.
Two hours into the swim, I reached the first bridge, approximately 12 km in. The tide had begun to assist, especially in the narrower sections where the river’s current sped up to around 3 km per hour. Combined with my swimming pace of 1:15 per 100m, I was cruising at nearly 8 km per hour.
Midway through the swim, I hit a mental wall. My forearms ached from maintaining my stroke, and I kept hitting my hand on the boat. The cold was seeping in. But after a quick feed, I reset mentally and powered through.
With 10 km to go, the wind picked up, turning the once-calm river choppy, and stirring up a head-on swell. Feeding became tricky as the boat rocked with each wave. My stroke adapted to cut through the chop, but the conditions slowed me significantly, reducing my pace to just under 2:00 per 100m. This unpredictability is part of the sport’s beauty.
The Tasman Bridge, marking the finish line, seemed to never get closer. But when I finally swam under it, I was overwhelmed with a mix of pride and sadness- pride for completing my longest swim and sadness that the challenge was over. My final time was 5 hours and 59 minutes, just under the six-hour mark and about 20minutes off the record.
Post-swim, I felt surprisingly good, both mentally and physically. Compared to a decade ago, I have lost the speed that I once had, but I'm ok with that.
My stomach handled the sports gels well, and after a nice warm shower we indulged in some celebratory burgers and beers at a local brewery before heading home to Melbourne the next morning. Returning home, my two-year-old daughter was oblivious to my achievement, simply wanting to play with her dad.
Key Information:
- Location: Hobart, Tasmania, Australia
- Event: Derwent River Big Swim (Website)
- Distance: 34 km (tide-assisted)
- Water Temperature: 16 degrees in December
- Skipper: Val (Website)
- Difficulty: Moderate (tide assistance helps, but the cold adds a challenge)
