PLA "bargies" know their onions!
They’ll be among 11 teams competing in The Transport on Water: Barge Driving Race.
The crews will use 30 foot oars and the tide to propel them along the seven-mile course.
The PLA team is under particular pressure this year because the authority's barge "Blackwall" won last year's event.
Mick Russell, skipper of the PLA crew, said: "We’ll be defending our title, so the pressure's on.
"It's impossible to say what the outcome will be because an individual barge's performance depends on the river and weather conditions on the day. But the lads will be giving it 100 per cent.
"It's always a good race and really pulls the crowds."
The event begins at 12noon. The barges or lighters are divided into three classes and each class has a different start point. They are off Greenwich Pier, Trafalgar Tavern, and Tunnel Glucose Wharf.
The race should finish between 2.30pm and 3pm at Westminster Bridge.
PLA Harbour Service Patrol Boats will be in the area throughout the competition to ensure the safety of competitors and other river users.