By chance, we stumble on Dangar Dory Derby Day held every Easter Sunday since the Eighties at the namesake island on the Hawkesbury River just north of Sydney. There is a riot of kids and watchful elders flailing in all manner of paddle craft on the beach alongside the café and wharf.

A sign for the Derby on a street pole reads: no smelly boats, just smelly people. Below it is another sign for the screening of Mamma Mia with mulled wine the local fire station. That was last night and today there are some heavy heads about.

To win the coveted Dangar Dory Derby Day trophy, which dates back to 1982, you must have a rowboat capable of carrying three people in reasonable safety. The point is to encourage human-powered commuting. The main race is around the island and the record is 15 minutes and 45 seconds, I’m told.

It’s then that several rowboats with similar dimensions catch my eye amid the motley fleet pulled up on the beach. Investigations reveal they are Dangar’s most popular craft, the mighty Swift Dory, regarded as a green alternative to the ubiquitous tinnie.

Australian boat builder John Murray, who makes the Swift Dory, says it can do six knots if you lean on the oars, cruise at five knots and carry four people. He says locals can reach the mainland, a kilometre to the south but seemingly a world away, in 10 minutes. Why bother starting the cantankerous outboard?

Of course, dories were originally designed to fit inside each other for use on fishing schooners, but their flat bottom permits the use of relatively narrow hulls, which leads to a terrific turn of speed and stability.

As it transpires, Murray, who also has a patented rowlock system and makes his own oars, has built about 30 Swift dories for keen rowers from Tasmania to Noosa in the last few years.

He first stumbled on a timber version of the rowboat when he was living on Dangar Island. Local ferry driver Jim Ray owned the beautiful boat. Murray was smitten and took a mould. He now builds the Swift Dories from fibreglass using vinylester resin.

The hull was originally based on an Adirondack Guide boat drawn up by the American Halsey Herreshoff in 1947. Herreshoff described it as "falling between the fragile racing scull and the heavy ill shaped row boat of several hundred pounds".

The dory was later refined by famous American small-boat designer John Gardner for more lift in the bow and, thus, greater seaworthiness. Murray emphasises the fact that the rowboat is perfect for a family. There is a link on his website (address below) to some video footage revealing as much.

Meanwhile, as I said, every waterway has its hidden treasures. Go looking for them. We never did find out who won the race, as we set off for more island exploration. But whether a visitor or local, everyone on Dangar Island has a common interest: they come by boat, ferry, tinnie and, increasingly, dashing dory these days.

And after speaking with owners of some of the bigger liveaboard passagemaking boats in recent editions of Tradeaboat, more and more people are putting rowboats on their motherships to keep fit when the anchor is down. Of course, rowing is an art in itself. I think I might go in training. See you at the Dangar Dory Derby Day next year.

The Swift Dory has air tanks for buoyancy, timber trim for eye candy, a foot brace, and a rudder that is said to be snag-free. The hull measures 5.5 metres long, 1.2 metres wide, and tips the scales to 51kg. You can buy one for $2800 race ready with oars. More from