Beowulf vs. Brecca

So the sea swimmers stood at shore
Stretching silently, side by side,
Awaiting the tide to turn for their journey.
To begin, Beowulf and Brecca, boasting how
They would be the winner, returning thither
From across the cold and forbidden ocean.
The water was calm, and also warm
As the sun so brightly shined its light.
The friends could never guess their venture
Would prove so brutal for two youths
To endure. Their duel driving them doubtlessly
Into the briny bilge, below them beasts
Swim circling, secretly surrounding them.
The water turned, churning and surging,
Dividing the dare-doers, deep in the darkness.
Beowulf was washed away, while
The sea-beasts of the deep attacked.
Brandishing his broadsword boldly, Beowulf
Hacked the helpless horrors, hewing them
to lifeless pieces of limp flesh.
Again and again, the beasts fought back, but
Could not break his rock hard chain mail.
Slowly the corpses sank to the sea-floor as
Beowulf resumed his sea journey.
Brecca was barely bothered by the beasts and
Had finished his swim first in victory,
But Beowulf's battles with the beasts from below
The waves were very valiant and vigorous.
Who won the war of the wide water?
Bronstan's son who easily won? Or
Beowulf, who battled beasts in the night?