How is Beowulf an epic poem and how is Beowulf an epic hero? How is the Old English poem "The Seafarer" relevant to these questions?

The term “epic” has been usefully defined as
follows:

It is a poem that is (a) a long
narrative about a serious subject, (b) told in an elevated style of language, (c)
focused on the exploits of a hero or demi-god who represents the cultural values of a
race, nation, or religious group (d) in which the hero's success or failure will
determine the fate of that people or nation. Usually, the epic has (e) a vast setting,
and covers a wide geographic area, (f) it contains superhuman feats of strength or
military prowess, and gods or supernatural beings frequently take part in the action.
The poem begins with (g) the invocation of a muse to inspire the poet and, (h) the
narrative starts in medias res [into the middle of things]. (i) The
epic contains long catalogs of heroes or important characters, focusing on highborn
kings and great warriors rather than peasants and commoners. [see link
below]

The Old English poem Beowulf is
an epic in practically all of these senses, with the possible exception of “e” and the
definite exception of “g.” Beowulf definitely represents the ideal values of his nation
(the Geats) and religious group (early Christians. His battles with the first two
monsters help determine the fate of the Danish people, while his battle with the dragon
helps determine the fate of his own people, the Geats. The poem opens with a long
catalogue of previous Danish kings, and Beowulf’s enormous strength, his lofty values,
and the fact that he fights on behalf of clear and lofty ideals all help make him an
epic hero.

In contrast, the Old English lyric poem “The
Seafarer” lacks almost all of the characteristics cited above. The speaker of this poem
is certainly heroic in the sense that he has survived much physical and emotional pain
and also in the sense that he actually seeks out challenging situations.  However, “The
Seafarer” is mainly a poem about a representative human being whose problems are mainly
personal. He fights with no obvious monsters but instead seeks and displays spiritual
strength. He is certainly more "heroic" than complacent people who live comfortably in
cities, but he fights no battles on behalf of others. He spends much of his poem
lamenting (understandably!) the sorrows he has endured – behavior not typical of the
kind of epic hero epitomized by Beowulf.

"The Seafarer" is
a much shorter poem than Beowulf and thus lacks the wide temporal
scope we often associate with epics.  Homer's Iliad describes
events that take ten years to complete.  His Odyssey describes
events that take place over another ten years. The time scheme of
Beowulf is, if anything, even broader, since the poem begins with
Beowulf as a young man in the prime of life and ends by focusing on his old age, fifty
years later. One senses that "The Seafarer" also covers more than a few years, but it
does not seem to cover anything like the extended time period mentioned in
Beowulf.