Needing precise teamwork, endurance and power, few sports are as challenging as rowing.
Add in a serpentine course four times longer than a normal race and you've got a serious gut check.
That's what two ADF crews faced when they lined up alongside 270 Australian and international boats in one of the world's foremost head regattas, held in Melbourne on November 25.
It was the first time ADF rowers have raced in the Head of the Yarra, a twisting eight-kilometre course between the CBD and Hawthorne.
In a head race, boats get a rolling start at 10-second intervals.
The ADF men's and mixed eights both placed sixth in their categories, finishing in 31 and 33 minutes respectively.
Men's eight coxswain Pilot Officer Alice Clayton said, because of its complexity, the race was dubbed the 'coxswains' course'.
"It was down to myself to steer and navigate the corners and bridges - some you could fit two boats through one arch, others you could only fit one," Pilot Officer Clayton said.
The Melbourne Girls College alumni, who grew up navigating the Yarra's turns, managed to avoid obstacles and other boats.
Others weren't as fortunate.
"A lot of coxswains hadn't rowed or steered on the Yarra before, so quite a few ended up in low-hanging trees or on the bank," Pilot Officer Clayton said.
But it wasn't just the tricky course that posed a threat.
With boats starting at different times, collisions occurred as crews raced to overtake those in front.
Stroke of the mixed eight Leading Seaman Holly Kilmartin, said half way through the race, one competitor's oar "caught a crab" while passing, causing two boats to crash.
The ADF mixed crew got a time penalty - slower boats must yield if an overtaking boat is within half a length.
Captain Ethan Dalton, of the United States Marine Corps, who is posted to Headquarters Joint Operations Command near Bungendore, sat two seats behind Leading Seaman Kilmartin.
He cut his teeth rowing on the Severn River in Maryland with the US Naval Academy before studying at Cambridge University and rowing on the River Cam, which, he said, was comparable to the Yarra.
"The Thames is unique with the strength of the current, but the River Cam is narrow with a lot of turns - there's a lot of clashing oars and bumping with other boats," Captain Dalton said.
"It's an exhilarating and thrilling experience."
The Head of the Yarra started in 1957.
Along with the Head of the River in London and Head of the Charles in Boston, it's considered one of the major international head races.
More than 2500 rowers participated this year, making it the biggest single-day regatta in Australia.
