In Chapter 3, Phillip and his mother manage to make it to a lifeboat when their ship is torpedoed, but Phillip is hit on the head and knocked unconscious. When he awakens, he finds himself on a raft with "a very old Negro" and the cook's cat. There is nothing else within sight except the endless sea and a few birds flying above. The Negro, Timothy, believes they are "somewhar roun' d'cays", and says they are lucky to have salvaged "a few biscuit, some choclade, an' d'matches". Although he is hopeful they will be found soon, he is adamant that they conserve what they have. Phillip, angry because Timothy will only give him a little water, remembers that his mother did not like Negroes because "they (are) not the same as (us)", and Phillip begins to think that she was right.
A summary of Chapter 4 can be found at this link : http://www.enotes.com/cay/q-and-a/what-summary-chapt-4-cay-6893.
In Chapter 5, a plane passes overhead, but apparently does not see Timothy's flare. Phillip is disheartened, and sits stroking the cat. Timothy says the cat is "not good luck". Phillip asks Timothy to tell him "what's out there, and Timothy describes the "miles o' blue wattah", the fish, and the cloudless sky above, becoming, in a sense, Phillip's eyes.