Þorkell (ÞGísl) is named as the poet of Búadrápa in ÓT (1958-2000, 180), but beyond that nothing is known about him and his name does not appear in Skáldatal.
Emily Lethbridge and Diana Whaley 2012, ‘(Introduction to) Þorkell Gíslason, Búadrápa’ in Diana Whaley (ed.), Poetry from the Kings’ Sagas 1: From Mythical Times to c. 1035. Skaldic Poetry of the Scandinavian Middle Ages 1. Turnhout: Brepols, p. 941.
The storm pelted very sharply on the mountains of lobsters [SEA]; stallions of the stems [SHIPS] bounded across the plains of the clew-line [SEA]. The dark breaker washed prows; the singeing-cold billow dashed off the surf-animals [SHIPS]; the raging wave impelled the keel.
The draught animals of currents [SHIPS] carried the mind-firm warriors to the lands of the ruler [Hákon]; the clatter of shields [BATTLE] closed in. Far-reaching Norway halted many ship-prows; weapons are harsh towards targes; fresh provisions were given to ravens.
The army carried the standard high; the terrible storm of edges [BATTLE] hit the shirts of Hamðir <legendary hero> [MAIL-SHIRTS]; the troop of men attacked. Stones and missile-points injured the lives of seamen; most shields were shattered; grey points crashed.
The troop used its hands; the storm of blades [BATTLE] was fierce; the harm of shields [SWORD] was eager for the lands of the helmet [HEADS]. Spear-trees [WARRIORS] fell; arrows flew from the bowstring; swords sang loudly against readied shields.
The hawks of the corpse [RAVENS/EAGLES] screamed; sharp wound-leeks [SWORDS] slashed the limbs of the troop; stones beat men. Grey metal weapons crashed on the supports of the helmet [HEADS]; helmets burst apart; there was no peace for the mountains of the hawk [ARMS].
Each hailstone weighed an ounce; gore spurted onto the sea from the wounds of men; blood washed the oars of the wound [SWORDS]. The slain fell there widely; [one] saw gilded standards sway; the company fought boldly on the warships of the jarls.
The very ugly troll-woman shot sharp arrows from her fingers; such is a trial for brave men. An extremely savage storm and sky-blizzard arose against the mighty men; the clash of shields [BATTLE] was loud.
The most powerful endower of battle-gulls [RAVENS/EAGLES > WARRIOR] leapt from the hull of the horse of the boat-shed [SHIP]; the snake of wounds [SWORD] was gladdened. The wave of the wound [BLOOD] poured down; the valiant Búi took a chest in each of his hands; I think men missed out on peace.
Vagn felled warriors; the sharp-eyed raven chose between stiff corpses; blood flowed onto the gunwale. Eiríkr managed nevertheless to clear completely the ship of that destroyer of wound-embers [SWORDS > WARRIOR = Vagn]; the din of steel weapons [BATTLE] was loud.