Every piece of equipment on board a whaleship had a purpose and sea shanties were no different. There were songs for heaving (pushing), songs for hauling (pulling), songs for jobs that required a steady rhythm and others for jobs that called for short bursts of power. It was the shantyman’s job to find the best tune to match each job. He was the man who led the way when shanties were being sung, setting the pace and rhythm of the work. This could be tricky since a song that was too fast or too slow could make the work harder not easier. Although it was not an official position, the shantyman often had a better voice, a good memory and could keep the songs on key, making sure the men kept time together. A good shantyman could make up new words on the spur of the moment which was an important skill since the song had to last until the job was done. Many of the shanties had two parts, the verses and a chorus. The shantyman would generally sing the verses while the sailors joined in for the chorus, heaving or hauling in time with the music. The shape of the tune helped the men know when to pull and as the shantyman sang the chorus they had a chance to catch their breath and get their hands ready for the next great burst of effort.
Martha's Vineyard Museum Pyle