The Duchess of Edinburgh is patron of the Association of Sailing Training Organisations, whose vessels are moored in St Peter Port.
Twelve yachts arrived over the weekend to prepare for the Guernsey to Poole small ships race.
Each is commanded by experienced skippers and mates, with the rest of the crew comprising the youngsters, who are aged between 14 and 25.
For many, it will be their first time at sea.
Sophie, formerly the Countess of Wessex, is the patron of the Association of Sailing Training Organisations.
Today, she will meet many of the youngsters taking part and will enjoy sail training aboard one of the competing yachts.
Sarah Creasey is the principal of the Guernsey Sailing Trust and says it is a wonderful opportunity for young people;
"Sailing is such an incredible sport and has so many benefits for mental and physical well being. We are excited to welcome an organisation with similar aims to our own to Guernsey. We look forward to the opportunities that this will provide in the future for young people.”
The race between Guernsey and Poole begins outside Castle Cornet at 2.30 pm on Tuesday 13 August and will take two days or less, depending on the weather.
It celebrates 200 years of the RNLI.
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