In 'Moby-Dick', the ship that rescues Ishmael after the Pequod sinks is the Rachel.
The Rachel is a whaling ship commanded by Captain Gardiner. After the Pequod is destroyed during Captain Ahab's final pursuit of Moby Dick, Ishmael survives by clinging to the coffin that had been made for Queequeg. The Rachel later finds him alone at sea and brings him aboard.
The rescue is easy to overlook because the novel's climax focuses on Ahab, Moby Dick, and the destruction of the Pequod. Ishmael is the sole survivor, which makes the Rachel's arrival essential: without it, there would be no narrator to recount the voyage. The novel's famous epilogue begins with his survival at sea.
The Rachel had already encountered the Pequod before the final chase. Captain Gardiner asked Ahab to help search for a missing boat containing his son, but Ahab refused because he was determined to continue after the white whale. The ship's name also carries a biblical association, evoking Rachel mourning for her children.