There are 3 stanzas in this poem. The sea is compared to a giant, grey, hungry dog. Here, the poet has used a metaphor of the dog to describe the various aspects of the sea. The poet sees the sea in its various moods and aspects - during the day and at night; at low tide and high tide, when it is calm, and when it is turbulent. Thus, three stanzas in the poem depict three stages of the sea / or the different moods of the sea.

The poet compares the sea to a dog displaying a variety of behaviors: when the dog is hungry, when it is hunting and when it is satisfied and sleepy. So, it is a perfect metaphor and the poet makes the image a perfect match. That comparison suggests that the dog has much in common with the sea.