1) Air 2) Chanty 1) Chanty 2) Sea air 3) Sea chantey 4) Shanty 5) They can sing it at sea 
A song, usually of a seafaring nature. Sometimes also spelled chantie or shanty (usually pronounced shan-tee).
• (n.) A sailor`s song.
Chant'ey noun [ Confer French chanter to sing, and Chant . noun ] A sailor's song. « May we lift a deep-sea chantey such as seamen use at sea?» Kipling. 
[n] - a rhythmical work song originally sung by sailors
chanty noun a rhythmical work song originally sung by sailors
(also chanty, shantey or shanty) A song sung by sailors to the rhythm of their movements while working.
a sailors' song, esp. one sung in rhythm to work.
Song sung together by sailors or pirates in unison, while they work