A Freedom Flotilla vessel began its journey on Sunday towards Gaza in an effort to break Israel's blockade on the Palestinian territory.
The ship, named Handala, is carrying humanitarian aid, 19 pro-Palestine activists and two journalists to the shattered enclave, which has been under total siege by the Israeli military for more than 21 months.
The boat departed from the port town of Gallipoli in southern Italy on Sunday morning, more than a month after another flotilla vessel, the Madleen, was intercepted by Israeli forces as it approached Gaza.
Ahead of the vessel's departure, the Freedom Flotilla said it had been targeted by what appeared to be two acts of deliberate sabotage.
A water tank delivered to the boat had been filled with sulfuric acid, burning two crew members, and a rope was found tied to the vessel's propellor.
The flotilla called on authorities to investigate the incidents and vowed to continue the mission.
"Despite this suspected sabotage, we remain undeterred. The attempt to harm our team and silene this mission will not succeed," it said in a statement on Sunday.
Handala, a former Norwegian trawler, is carrying medical supplies, food and children's equipment to Gaza. The 1,800-kilometre journey is expected to take around a week to complete.
The boat is named after the iconic cartoon figure created by the late Palestinian artist Naji al-Ali. The flotilla said the vessel carries "the spirit of Handala and the spirit of every child in Gaza deprived of safety, dignity and happiness".
The Freedom Flotilla Coalition is a grassroots international network of activists who have been trying to break Israel's blockade on Gaza since 2010.
"The flotilla is a collective act of conscience," said Huwaida Arraf, a human rights lawyer and member of the flotilla's steering committee.
"We are everyday people from around the world standing together to confront Israel's ongoing war crimes and to affirm the right of Palestinians in Gaza to live with freedom and dignity," she said.
Handala is the second boat the flotilla has sent to try to break the siege. The first ship, the Madleen, was stormed by Israeli forces less than 200 kilometres from the Gaza coast.
The military detained all 12 activists on board, took them to Israel and deported them from the country.
Climate activist Greta Thunberg and European lawmaker Rima Hassan were among those on board.