Ellen MacArthur Cancer Trust sailing challenge for cancer patients
About 100 young people recovering from cancer are taking to the UK's seas in a "confidence-building" project run by yachtswoman Dame Ellen MacArthur.
Round Britain 2017, organised by the Ellen MacArthur Cancer Trust, will take place between May and September and will visit more 60 towns and cities.
Young people aged eight to 24 will be taking part, in relays.
Dame Ellen, founding patron of the charity, broke a record for the fastest solo circumnavigation of the world.
One of those taking part, Hannah Spencer, said she "wouldn't be here" without the trust.
The 23-year-old, from Belper, Derbyshire, was diagnosed with chronic myeloid leukaemia in 2009 and will work as a volunteer mate on the voyage.
"The trust has had a massive impact on my life and I definitely wouldn't be here without them," she said.
Crew member Tom Roberts, from Ripley, North Yorkshire, was diagnosed with Ewing's sarcoma - a form of bone cancer in the spine - on his 16th birthday and has been involved with the trust since 2010,
He said he was taking part in the challenge "to ensure that others continue to benefit from the trust the same way I have".
The sailing journey takes in Cowes, Cardiff, Glasgow, Belfast, Plymouth, Bristol, Liverpool, Edinburgh, Newcastle, Hull, London and Southampton.
The crew will visit cancer treatment centres where they will meet other young people who are still in recovery.
My story: Jessica Cunningham, 22, from Camberley, Surrey
I was first diagnosed with Hodgkin's lymphoma in January 2014.
I was working at the time and in a place where I was looking to maybe study and just do everything really.
It was very shocking getting the diagnosis and then a massive challenge to have to get my head around that, going into treatment and then working through it.
I've had chemotherapy, radiotherapy, two stem-cell transplants and I have regular check-ups.
I've got the all-clear now and I am very much looking forward to sailing in the summer.
I was introduced to the trust through my youth worker. I later applied to be part of Round Britain and am very excited to have been selected for the leg from London to Cowes, via Southampton.
Sailing has helped me build my confidence considerably as well as allowed me to socialise with people of a similar age, going through the same treatment I have.
It's a return to normality in a way - going back to work and doing all the activities I never thought were possible.
Dame Ellen, who is based on the Isle of Wight, said: "Round Britain is about a lot more than sailing.
"It is about rebuilding the confidence, self-belief and independence of those involved - bringing back in to focus positive options which have been unimaginable during treatment."
She added she hoped the trip would "highlight just how incredible and courageous these young people are", as well as "raise the profile" of the charity.
In 2005 Dame Ellen broke the world record for the fastest solo circumnavigation of the globe. The current record holder is French yachtsman Thomas Coville.