The Anglo-Saxon poem "The Seafarer" is one hundred and twenty-four lines long; the first twenty five of them are thematically linked and can therefore be considered "the beginning," as you mention in your question. In those first twenty-five lines, most of the imagery centers around the cold conditions which cause the seaman such misery.
The deep coldness of the sea is seen over and over in the sensory imagery of this section of the poem. The sailor is "sweating in the cold" during his time at watch, his feet are "cast in icy bands" and tied down with "icy chains." The sea itself is "ice-cold," "hung with icicles" and fraught with "freezing waves."
This tale is true, and mine. It tells
How the sea took me, swept me back
And forth in sorrow and fear and pain,
Showed me suffering in a hundred ships,
5 In a thousand ports, and in me. It tells
Of smashing surf...
(The entire section contains 433 words.)