In John Masefield's poem "Sea Fever," the speaker begins with the words "I must down to the seas again." This tells the reader that he has been a sailor before, and feels an irresistible compulsion to return to the sea-faring life. Descriptions of life at sea fall broadly into two categories. Some people feel trapped in close quarters; in prison, as Dr. Johnson put it, with the additional possibility of drowning. Others feel far freer than they did on land, adapting to be part of the ship, with the wide oceans of the world on which to roam.
Masefield is evidently one of the latter party. Whenever he writes about sailing, it is will a sense of adventure, excitement, and freedom, and it is this exhilarating sense that is the theme of the poem. The speaker expresses affection for all the sounds, sights, and sensations of sea-faring, which are clearly familiar to him. The scenes he depicts are bracing ones:
And all I ask is a windy day with the white clouds flying,
And the flung spray and the blown spume, and the sea-gulls crying.
The type of freedom for which the speaker yearns is summed up in the phrase "the vagrant gypsy life" in the final stanza. Some, who have the spirit of a gypsy, want to roam about the countryside. Others, whose conception of freedom is somewhat different, are only ever really at home on a boat.