The poem
Louder than gulls the little children scream Whom fathers haul into the jovial foam; But others fearlessly rush in, breast high, Laughing the salty water from their mouthes-- Heroes of the nursery.
The horny boatman, who has seen whales And flying fishes, who has sailed as far As Demerara and the Ivory Coast, Will warn them, when they crowd to hear his tales, That every ocean smells of tar.
Well, as the poem is supposed to be read as caused by the experience of war, those little, screaming boys, whose fathers pull to the sea and those who bravely go there themselves are as the two type of soldiers. both types are like little boys because they are young and inexperienced, know nothing about life. The first stanza could be ironic, especially the phrase:"Heroes of the nursery". they are not heroes maybe, who rush so eagerly in war, but they are only stupid and naive. The second stanza is more mysterious in my reckoning but it is surely a warning of war