Green’s Dictionary of Slang

1. (US Und.) a flat-bottomed boat.

1848

Ladies’ Repository (N.Y.) Oct. VIII:37 316/2: Noah, a flatboat.

2. (US) a poached egg.

1902

N.-Y. Trib. section II, 27 July 2: ‘Give me some poached eggs on toast,’ you say, ‘and a cup of coffee.’ The waiter turns toward the kitchen and shouts, ‘Noah on a raft!’ Then he wheels toward the steaming, polished coffee tanks and cries, ‘Draw one!’.