Kate, 34, arrived at the event looking suitably nautical in a smart skirt and blouse teamed with a pair of heels.
However, she quickly changed into a much sportier ensemble, including a waterproof jacket and trousers and a £90 pair of Adidas trainers, to show of her skills at the helm of test boat T1 - a foiling AC45 catamaran.
Accompanied by Sir Ben Ainslie, the most successful Olympic sailor in history, Kate was pictured laughing happily as they completed a training circuit on The Solent with his crew.
'I think the Duchess had a great time, it certainly looked that way. It was perfect sailing conditions, we had about 15 knots of wind, we were going up to 33 or 34 knots which is close to 40mph,' Ben revealed once the visit was complete.
'The Duchess was steering the boat for about half of the session and I think the guys were all really impressed with how well she had sailed. She had done a bit of sailing before. We had a great sail, it was a blast and she thoroughly enjoyed it.'
He added that Kate's skills had given his own a run for their money, explaining, 'There were a few moments from the front of the boat that she was a better helms person than I am so I wasn't too happy about that so you never know I might give her a place.'
Kate also revealed some ambitions for her two children, Prince George and Princess Charlotte, whilst on the boat trip, telling Ben that she was keen for them to start sailing sometime in the future.
'Whether that's down here or elsewhere - I'm sure there are some fantastic locations around the country and it would be great to see them sailing,' Ben said. 'It's always encouraging to see the next generation to come through.'