Five thirty in the morning. The darkness is punctured by single searchlight from the Greek coastguard and the captain’s radio message; insistent and repeated several times.
It’s the precise co-ordinates of migrants’ boat we’ve just spotted, bracketed by the words; "Turkey coastguard, Turkey coastguard."
The only response is silence. "They never answer these days," says one of the crew.
We’re on the Aegean Sea, in a narrow stretch of water between the two nations that has become this summer the busiest point of illegal entry into Europe.
The vessel we’re tracking is still outside EU waters. Under a deal with Turkey, it should be seized and turned round.
But as we’re seeing, the deal is already breaking down. And with the Turkish President Recep Erdogan threatening to "open the borders" if the EU opposes his Syrian incursion, the people smugglers are back in business.
A few minutes later the migrants' boat drifts over the maritime border and the Greek coastguard pulls alongside.
It’s an inflatable dinghy, barely seaworthy, crammed with more than 40 Africans.
The boat is a leaking death trap. As disposable to the traffickers as the cargo it carried.
"We were all so scared," says Alfonse, from Burundi. "At any time it could tip over. None of us can swim."
But the lure of a new life in Europe outweighs the dangers and the trip can be made for just a few hundred euro.
Still, as we discovered, what lies ahead falls far short of the promised land of their imagination.
In July and August alone, 12,000 arrived. Many end up in the notorious Moria camp on the island of Lesbos, a former army barracks designed for 3,000 migrants, now an unhappy home for four or five times that number.
Winter is coming; but they pitch flimsy tents amid the olive tree. One family we meet shares the same plastic sheeting as three other families.
One in three of the new arrivals are unaccompanied children.
"They suffer the trauma of the journey here; then a second trauma of the living conditions," Ihab Abassi, of Medicins Sans Frontieres, says.
He wants Europe to act; Greece wants the EU to share the burden. But they’ve been saying that for years, and little has been achieved.
For a while, the accord with Turkey, which received six billion euros in return, stemmed the flow.