Here’s my translation

Alan

Þeir sáu nú, hvar fugl fló af landi ofan, sá er skergípr heitir. 
They saw now, where a bird flew from land downwards, that-one (ie the bird, masc) which is-called a skergípr (skerry-swift? see note below or perhaps skerry-fiend, related to -gífr?)

The Irish Times, Dec 29, 2008 – The Yorkshire name Gipp is from Gípr, “drunkard”. The great lexicographer, Skeat, could trace his name to the Old Norse Skjótr, “swift”.

see also Hrólfr gípr in Valla-Ljóts saga.

Hann hefir höfuð svá mikit ok hræðiligt, at honum er jafnat til fjándans, ok réðst á móti drekanum, ok var þeira atgangr hræðiligr. 
It has a head so large and dreadful,  that (it) is likened with it to the-devil (ie the bird is likened to the devil), and (it) set-itself (ie made-an-assault) against the-dragon, and their fighting was dreadful.

En svá lauk þeira viðskiptum, at þeir fellu báðir niðr, ok fell skergíprinn niðr í sjóinn, en drekinn kom niðr í skipi Siggeirs. 
But (and) it concluded in their hostilities thus, that they both fell(in battle) down, and the-skergípr (skerry-swift-fiend) fell down into the-sea, but (and) the-dragon came down into Siggeirr’s ship.

Herrauðr var þar þá kominn ok lét ganga kylfuna á báðar hendr. 
Herrauðr was (had) then (ie by that time) come there and caused to the-club to go (into action) ( ie rain down blows, ganga, Z10) on both sides (lit: hands, hönd, CV.ii).

Hann sló til Siggeirs, ok kom höggit undir eyrat, ok brotnaði í honum allr haussinn, en hann hraut fyrir borð ok kom aldri upp síðan.
He struck at Siggeirr, and the-blow came under the-ear, and all the-skull (nominative) was-broken in him, but (and) he was-flung over-board and never came up again.

Hárekr konungr raknar nú við ok varð at einum gelti ok greip til Herrauðar með tönnunum ok reif af honum alla brynjuna ok festi tennrnar í brjóstinu á honum ok reif af honum báðar geirvörturnar niðr at beini, en hann hjó í móti á trýnit á geltinum, ok tók af fyrir framan augun. 
King Hárekr now recovers-his-senses and became (turned into) a certain boar (göltr=galti) and gripped at Herrauðr with the-teeth and ripped all the-coat-of-mail from him, and fastened the-teeth into his breast, and ripped both nipples from him down to (the) bone), and he hewed in return at (the) snout on the boar, and took (it) off (right) in-front-of the-eye (sg). (presumably the point where the snout meets the eyes).

Var Herrauðr þá svá móðr, at hann fell á bak aftr, en galtinn trað hann undir fótum sér, en gat eigi bitit, er af var trýnit.
Herrauðr was then so exhausted, that he fell back on (his) back, but (and) the-boar trod him under its feet, but (it, the boar) was-not-able to (geta + pp) bite, when the-snout was off (ie missing).

Þá kom at glatunshundtík mikil á skipit ok hafði stórar vígtenn. 
Then a great hell-hound-bitch came at (them) on to the-ship and (she/it) had large tusks (canines, fangs).

Hún reif gat á náranum á geltinum ok rakti þar út þarmana ok hljóp fyrir borð. 
She (it) ripped a hole in the-groin (nári, wk masc) on the-boar, and unwound (rekja) the-intestines out-of there and (she) leapt over-board.

En Hárekr var þá í mannslíki ok steypti sér fyrir borð eftir henni, ok sukku þau til grunna, ok kom hvárki upp síðan, ok þótti mönnum sem þat mundi verit hafa Busla kerling, því at hún sást aldri síðan.
But Hárekr was then (by that time) in human-form and plunged over-board after her (it), and they to sank to (the) bottom and neither-of-the-two came up after-that, and (it) was-reckoned by folk (men) like that would have been old-woman Busla, because she was never seen after-that.

15. Þeir fóstbræðr fengu sigr.
15. Those foster-brothers gain victory.

Bögu-Bósi er nú kominn upp á skip Hræreks ok barðist alldrengiliga. 
Bögu-Bósi is (has) now come up onto Hroerekr’s ship, and fought very-bravely.

Hann sá, hvar faðir sinn flaut með borðinu mjök máttdreginn. 
He saw, where his father floated by the-side-of-the-ship (borð, Z2) very sapped-of-strength

Stökk hann nú fyrir borð ok hjálpaði honum ok kom honum upp í skip sitt.
He sprang over-board and helped him and brought him up on to his ship.

Þá var Hrærekr kominn á skipit ok hafði drepit margan mann. 
Then (by that time) Hroerekr was (had) come to the-ship and had killed many a man (person, acc sg)

Bósi kom þá upp á skipit ok var mjök móðr, en þó réðst hann í móti Hræreki ok hjó í skjöld hans ok klauf hann allan niðr í gegnum ok af honum fótinn í ristarliðnum.
Bósi came then up on to the-ship and was very exhausted, but nevertheless set-himself (ie made-an assault) against Hroerekr and hewed into his shield and cleaved it all down through and (cleaved) the-leg off him at the-ankle-joint.