Sailors sang rhythmic chanteys (shanties) to:

•  Synchronize hauling on the lines (like the halyards which lift the yards)
  -- Haul Away Joe                           YouTube
• Synchronize rowing in old time fishing boats, like the fishermen from the barren island of Mingulay in the Outer Hebrides, off the coast of Ireland and Scotland 
  --Mingulay boat song                  YouTube 
• Entertain/boast/lament/exult
  --Rolling Down to Old Maui     YouTube

   

  Haul Away Joe When I was a little lad And so my mother told me,  Way, haul away, we'll haul away Joe,  That if I did not kiss a gal My lips would grow all moldy,  Way, haul away, we'll haul away Joe. Chorus: Way, haul away, we'll haul for better weather,  Way, haul away, we'll haul away Joe. Louis was the King of France, Before the Revolution,  Way, haul away, we'll haul away Joe,  King Louis got his head cut off Which spoiled his constitution,  Way, haul away, we'll haul away Joe. Oh the cook is in the galley Making duff so handy  Way,. haul away, we'll haul away Joe,  And the captain's in his cabin Drinkin' wine and brandy  Way, haul away, we'll haul away Joe.	Once I had an English gal, She was fat and lazy Way, haul away, we'll haul away Joe, Then I had an New York gal, She damn near drove me crazy Way, haul away, we'll haul away Joe Once I had an Irish gal, her name was Molly Bradigan Way, haul away, we'll haul away Joe She stole my shirt, she stole my watch, she stole my plate and pannikin [cup] Way, haul away, we'll haul away Joe. St. Patrick was a decent man, He comes from decent people. Way, haul away, we'll haul away Joe, He built a Kirk in Dublin town, And on it put a Steeple. Way, haul away, we'll haul away Joe [CHOOSE A NAME], he is a decent lad, He always does his duty. Way, haul away, we'll haul away Joe, And when we're in our bunks at night, The boys all call him cutie Way, haul away, we'll haul away Joe,
  Mingulay Boat Song Chorus Heel ya ho, boys, let her go, boys Turn her head round, into the weather, Heel ya ho, boys, let her go boys, Sailing homeward to Mingulay What care we how white the Minch is?  What care we, boys, for wind or weather?  Let her go boys; every inch is  Sailing homeward to Mingulay. Wives are waiting, at the pier head,  Looking seaward, from the heather;  Bring her round, boys, then we'll anchor  'Ere the sun sets on Mingulay.	When the wind is wild with shouting And the waves mount ever higher Anxious eyes turn ever seaward To see us home, boys, to Mingulay Sky or Lewes, Mull or Uest, Tyree, Kull or Vatersay, None can call us, like our Island Our own dear Island of Mingulay Far behind the peaks of Cullen We'll soon see our own land of heather And you know, boys, candles glow, boys Lighting the windows of Mingulay Ships return now, heavy laden  Mothers holdin' bairns a-cryin' They'll return, though, when the sun sets  They'll return to Mingulay.
  Rolling Down To Old Maui It's damn tough life, full of toil and strife We whaler men undergo And we don't give a damn when the gale is done How hard the winds did blow 'Cause we're homeward bound from the arctic ground With a good ship taut and free And we won't give a damn when we drink our rum With the girls of old Maui Chorus: Rolling down to old Maui, me boys Rolling down to old Maui We're homeward bound from the arctic ground Rolling down to old Maui Once more we sail with the northerly gale Through the ice and wind and rain Them coconut fronds, them tropical lands We soon shall see again Six hellish months we passed away On the cold Kamchatka sea But now we're bound from the arctic ground Rolling down to old Maui	Once more we sail with the northerly gale Towards our island home Our main mast sprung, our whaling done And we ain't got far to roam Our stuns'l booms is carried away What care we for that sound A living gale is after us Thank God we're homeward bound How soft the breeze through the island trees Now the ice is far astern Them native maids, them tropical glades Is a waiting our return Even now their big brown eyes look out Hoping some fine day to see Our baggy sails running 'fore the gales And now we're anchored in the bay, With the Kanakas all around With chants and sweet aloha-ohs They greet us homeward bound We'll go ashore and on a tear We'll paint them beaches red To wake up in the arms of an island maid With a big, fat achin' head