Volunteer crew and paramedics climbed on board just after 19:00 and arrived at Masline harbour to recieve the patient and meet with the Sark doctor and community first responders.
The patient was in Guernsey just after 20:30 and was swiftly taken to the hospital.
It was one of 30 calls St John Ambulance & Rescue received on the day including falls, traffic incidents and an airport medevac.
Ambulance & Rescue thanked the volunteer boat crew and Alderney ambulance crew who assisted with this case.