Ms Ras will teach midwifery skills while the crew distribute medical supplies, clothing, basic hygiene supplies, stationery, books and "all the other items we take for granted", Ms Kuczera said.
The siblings were still children when they last visited Vanuatu with their father. "We really liked it and wanted to spend more time there. I remember visiting some of the remote islands where people didn't have much. We brought a bunch of school books and the children were blown away."
She described the trip as "an adventure with a purpose".
"We want to give something back, so we're not just onlookers or tourists. And it's definitely something my father would like to see the boat used for."
Their mother and family members from France would join them for parts of the voyage.
With all the crew changes they expected 50 people to travel with them over the course of the six-month trip.
Ms Kuczera said the help and donations they had received had been overwhelming.
Bernard Kuczera, 63, disappeared in the Bay of Islands after heading out in a dinghy in May 2011. The coroner ruled last year he had most likely drowned. Sylfia was one of six steel ships built by the Polish adventurer.