The Open Arms vessel, carrying 200 tonnes of food, could be seen in the distance off the beach of the coastal strip, where it had been towed from Cyprus.
The charity World Central Kitchen (WCK) aims to deliver the aid on a temporary jetty, though precise details of how supplies would reach shore have not been made clear.
If the new sea route is successful, it may help to ease the hunger crisis affecting Gaza, where hundreds of thousands of people face malnourishment and hospitals in the worst-stricken northern areas have reported children dying of starvation.
However, aid agencies have repeatedly said that plans to bring in aid by sea and through air drops will not be enough to satisfy the territory's vast needs.
The war began with an attack by Hamas Islamist fighters from Gaza who killed 1,200 people and seized 253 hostages in Israel on Oct. 7, according to Israeli tallies. Since then, an Israeli assault has killed more than 31,000 people and driven nearly the entire 2.3 million population of Gaza from their homes.
Hamas presented mediators with its latest counter-offer for a weeks-long ceasefire, but this was rejected by Israel, which said it was based on "unrealistic demands".
Like earlier offers from both sides over the past two months of talks, the Hamas proposal, reviewed by Reuters, envisions the release of dozens of Israeli hostages in return for hundreds of Palestinians held in Israeli jails.
But it also calls for talks during a second phase that would eventually lead to the end of the war. Israel has persistently said it will discuss only temporary pauses in the fighting and will not discuss ending the war until Hamas is eradicated.
STILL WORKING ON A DEAL
Sami Abu Zuhri, a senior Hamas official, told Reuters Israel's rejection showed that Prime Minister Benjamin Netanyahu was "determined to pursue the aggression against our people and undermine all efforts exerted to reach a ceasefire agreement".
It was up to Washington to push its ally Israel to accept a ceasefire, he said.
U.S., Egyptian and Qatari mediators had hoped to reach a ceasefire in time for the Ramadan Muslim holy month, but that deadline passed this week. Egyptian President Abdel Fattah al-Sisi, whose country hosted the main negotiations this month, said he was still working hard to reach a deal.
The United Nations says all of Gaza's 2.3 million people are suffering from a food crisis and a quarter of them are on the precipice of famine, especially in the north.
Israel, which sealed off all land routes into Gaza apart from two crossings on the territory's southern edge, denies blame for hunger and says aid agencies should do a better job distributing food. The agencies say they need better access and security, both of which are the responsibility of Israeli forces who have blockaded the strip and stormed its cities.
TWENTY-ONE KILLED, 150 WOUNDED AT AID DISTRIBUTION
The distribution of the limited aid that arrives has been chaotic and frequently violent under the watch of Israeli tanks.
In one of the worst reported incidents yet, Gaza health authorities reported at least 21 people had been killed and 150 wounded on Thursday night, blaming Israeli forces for opening fire into a crowd queuing up for food at a road junction near Gaza City.
Israel denied its troops were to blame, as it has in past incidents, including the deadliest so far, on Feb. 29, when more than 100 people were killed.
There are increasing signs of friction between Washington and its close ally Israel over the conduct of the war, which officials in President Joe Biden's administration say is being waged with too little care for Palestinian civilians.
U.S. Senate Majority Leader Chuck Schumer, the highest ranking Jewish official in the United States and a leader of Biden's Democratic Party, called on Thursday for Israelis to hold an election and replace Netanyahu.
He described Netanyahu as an obstacle to peace who was destroying Israel's international standing. "Israel cannot survive if it becomes a pariah," Schumer said.
Netanyahu's Likud Party said his policies had widespread public support. "Senator Schumer is expected to respect Israel's elected government and not undermine it," it said. "This is always true, and even more so in wartime."
