Here’s my translation.

Alan

Þeir frétta nú, at þeir eru við land komnir Hárekr konungr ok synir hans, ok var nú eigi þusulaust.
They gain-intelligence now, that they, King Hárekr and his sons, are (have) reached (lit: come against) land, and (it) was now not without-a-spirting-out (ie they arrived in rioutious haste?, cf þusa, CV, a spirt, spirting out, and Þusa=þysja CV, to rush => Þyss, CV, noise, uproar, riot).

Lét Herrauðr nú leggja út skipum sínum á móti þeim; hafði hann lið mikit ok frítt ok þó miklu minna en þeir Hárekr.
Herrauðr caused now to lay his ships’ (course) towards them (lit: to a meeting with them); he had troops great and fine and yet much less (fewer) than they, Hárekr (and co).

Lagði sínu skipi á móti konungi Smiðr Þvarason, en Bósi móti Hræreki, Herrauðr á móti Siggeiri, ok þurfti þar eigi at sökum at spyrja, ok tekst með þeim bardagi mjök harðr, ok váru hvárirtveggju inir áköfustu.
Smiðr Þvari’s-son (nominative) laid his ship’s (course) towards (the) king, but (and) Bósi towards Hroerekr, Herrauðr towards Siggeirr, and (one) needed there not to enquire as to (the) effect (cf sök, CV.ii.3?) (ie it came as no surprise to anyone that…), and a very hard battle begins between them, and each-of-the-two (sides) were the most-fierce.

Ok er bardaginn hafði eigi lengi staðit, réð Siggeirr til uppgöngu á skip Herrauðs ok varð skjótt mannsbani.
And when the-battle had not been-going (lit: stood) for a long-time, Siggeirr attempted (ráða til e-s, Z16) a going-up onto Herrauðr’s ship and quickly became (ie was) a man-slayer.

Sniðill hét stafnbúi Herrauðar.
Herrauðr’s fo´c’s’le-man was-called Sniðill.

Hann skaut spjóti at Siggeiri.
He shot (launched) a spear at Siggeirr.

Hann tók spjótit á lofti ok skaut aftr at þeim, er sendi.
He caught the-spear in (the) air (ie in mid-flight), and shot (it) back at that-one (dat sg), who sent (it).

Spjótit flaug í gegnum Sniðil ok svá langt í skipsstafninn, at hann nisti hann þar við.
The-spear flew through Sniðill and so far into the ship’s-stem (probably the prow, fram-stafn), that he (ie Siggeirr, masc) pinned him (Sniðill, masc) there-with (ie with it).

Herrauðr sneri nú í móti Siggeiri ok leggr til hans með atgeir, svá at gekk í gegnum skjöldinn, en Siggeirr snaraði svá hart skjöldinn, at Herrauði varð lauss atgeirrinn, en hann hjó til Herrauðar, ok kom á hjálminn ok tók af fjórðunginn, ok fylgdi þar it hægra eyrat.
Herrauðr turned now towards Siggeirr and thrusts towards him with a halberd, so that (it) went through the-shield, but (and) Siggeirr twisted the-shield so hard, that the-halberd (nominative) became free from Herrauðr (ie he lost hold of it), but (and) he hewed at Herrauðr, and (the blow) came onto the-helmet and took off the the-fourth-part, and the-right ear accompanied (it) there.

En Herrauðr greip upp eina stóra ruddu af þiljunum ok laust á nasir honum, svá at hjálmblikit gekk at andlitinu, ok brotnaði í honum nefit ok ór honum allar tennrnar, ok stökk hann öfugr aftr á skip sitt ok fell þá í óvit ok lá mjök lengi.
But Herrauðr grasped up one large crude-club (probably one of the deck planks) from the-deck (gramm. pl, lit: planks) and struck on his (ie Siggeirr’s) nose (lit: nostrils), so that the helmet-visor went into the-face, and his nose (nominiative) was-broken, and all the-teeth (knocked) out-of him, and he sprang backwards back to his ship and fell then into insensibility and lay a very long time.

Smiðr barðist drengiliga.
Smiðr fought bravely.

Hárekr konungr komst upp á skip hans við tólfta mann ok ryðst um fast.
King Hárekr made-his-way up to his ship with (the) twelfth man (person) (ie eleven others) and clears-the-way (“cut a swath of destruction”, ryðja, Z5) around him firmly

Smiðr snýr nú á mót honum ok hjó til hans með saxi því, sem Busla kerling hafði gefit honum, því at hann bitu eigi atkvæðalaus vápn.
Smiðr turns now towards (lit: to a meeting with) him and hewed at him with that short-single-edged-sword (note: no ordinary weapon), that old-woman Busla had given him, because weapons of-no-importance (ie ordinary weapons, plural) bit (cut) him (ie the king) not.

Höggit kom framan um þverar tennrnar, ok brotnuðu þær ór honum allar, gómbeinit brotnaði ok varrirnar sprungu báðar, ok hljóp þar ór blóð mikit.
The-blow came on the front across the-teeth, and they all were-broken out-of him, the-mouth-roof  bone (palate bone, os paliti, CV) was-broken and both the-lips (vörr) split, and much blood ran (gushed) out-of-there.

En við þetta högg brá honum svá, at hann varð at flugdreka ok spjó eitri yfir skipit, ok fengu margir menn bana.
But (And) with this blow (it) changed (transformed?) him so, that he became (verða at e-u, Z8) a flying-dragon, and spewed poison over the-ship (sg), and many men (persons) received death.

Hann steypti sér niðr at Smið ok gleypti hann ok svelgir honum niðr í sik.
He hurls-himself down at Smiðr and swallowed him and swallows him down into himself.