Sophie, and her husband the Earl of Wessex, heard about the Sail-Ability programme, which offers people with disabilities, especially children, the opportunity to get involved in water activities.
The countess first sounded a loud horn to signal the start of a boat race between Duke of Edinburgh students, before saying: “I didn’t value my hearing at all.”
She then proceeded to help wheelchair user Alexzandrina Looby, who is in her 40s, into a boat by lowering her down gently using a winch.
Ms Looby was one of a small number of people who have benefitted from the programme that Sophie and Edward saw in action on Monday.
Before leaving the National Sailing Academy, the countess was given a card by eight-year-old Aleccai Brown which read: “Welcome to Antigua… Edward and Sophie” followed by a picture of the island’s flag.
Young Aleccai is a pupil at the Victory Centre, which is a non-profit special needs school based on Antigua.
The countess then gave the youngster two hugs before departing for another engagement.