Here’s my translation

Alan

Þórir bað sína menn hlífa sér og gæta síns sem best. 
Þórir bade his people (men) to protect themselves and take-care-of themselves as best (they could).

Tókst þá ei mannfallið allskjótt. 
The-loss-of-life (fall of men in battle) did not (ei, Z2, based on this texts use of ei previously) take-place then very-speedily.

Þá kom Halldór til liðs við Þóri við tólfta mann. 
Then Halldórr came to (the) aid of Þórir with (the) twelfth person (man) (ie with eleven other men)

Þeir börðust nú um hríð. 
They fought now for a while.

Urðu menn sárir af hvorum tveggjum. 
People (men) became (were) wounded from each two (sides).

Og þá komu njósnarmenn þeirra Steinólfs og segja að eigi mundu færri menn ríða inn fyrir Króksfjarðarmúla en fimm tigir. 
And then came (the) spies of them, Steinólfr (and co) and (they) say that fewer men than fifty (five tens) would not ride in over Króksfjarðarmúli (Hook’s-Fjord’s-Mull)

Þeir segja og mikið lið ríða frá Gróstöðum.
They say also (that) a great troop rides from Gróstaðir (Gróa’s-Steads).

Þá kallar Steinólfur á sína menn og biður þá halda til skipa og láta þau gæta sín. 
Then Steinólfr calls to his people (men) and asks them to hold (course) for (the) ships (plural) and cause them (ie the ships) to take-care-of themselves.

Snúa þeir Kjallakur þá út undir bakkana og til skipa sinna en hinir hlupu eftir þeim. 
They, Kjallakr (and co) turn (go) then out under the-bank and to their ships (plural) but (and) the-others ran after them.

Skipið var uppi fjarað. 
The-ship was left-aground (lit: the-ship (acc) was-ebbed up)

Þeir Jósteinn hrundu fram skipinu en Þorvaldur bróðir hans hélt upp bardaganum á eyrinni við Þóri. 
They Josteinn (and co) pushed the-ship forward but (and) Þorvaldr his brother kept up the-battle on the-sand-bank against Þórir.

Vöflu-Gunnar kom að þar er Jósteinn hafði flotað skipinu og hjó hann í sundur í miðju við saxinu en brýndi upp skipinu. 
Vöflu (Wavering)-Gunarr came to there where Josteinn had floated the-ship and hewed him a-sunder in the middle (‘amidships’, ie cut him in half) with the-short-single-edged-sword but (and) dragged up the-ship (half-ashore) (brýna, Z2)

Þeir Þórarinn koma þá á eyrina er Þorvaldur var fallinn og flestir allir hans menn.
They Þórarinn (and co) come then to the-sand-bank where Þorvaldr was fallen (in battle) and most all his people (men).

Hann bað menn hætta að drepa niður forystulausa menn: "Höldum heldur eftir þeim Steinólfi og látum nú sverfa til stáls með oss."
He bade people (men) to cease (hætta is also listed in Z) to kill off (lit: strike down) unprotected people (men): “Rather (let-us) pursue them, Steinólf (and co) and (let-us) cause (them) now to fight-to-the-last with us.”

Þórir kvað þá fyrr ná mundu skipum sín en þeir yrðu teknir. 
Þórir declared them (ie that they) would reach their ships sooner than (fyrr…en, ie before) they (the men, not the ships) became (ie were) taken (captured).

Þórarinn kveðst eiga teinæring "er marga menn mun bera og eltum þá suður yfir fjörð."
Þórarinn declared-of-himself to have a ten-oarer (ie a ten-oared boat, CV) “which will carry many men and (let-us) pursue them south over (the) fjord.”

Þórir bað hann ráða en kveðst svo hugur um segja að þá væri best að skilja. 
Þórir bade him to have-his-own-way (ráða, Z9) but declared-of-himself to forbode (see hugr, Z4) that (it) would-be best to part them (þá, acc) (ie that they should part, skilja, impers. Z4)

En Þórarinn vill ekki annað en að fara eftir þeim. 
But (And) Þórarinn wants not other than to go after them.

Reið hann heim til skips með tuttugasta mann en Þórir gekk á skip með nokkura menn. 
He rode home to (his) ship with (the) twentieth (person) man (ie with nineteen others) but Þórir went aboard (his) ship with some people (men)

Menn Þóris voru bæði sárir og vígmóðir og gekk seint róðurinn. 
Þórir’s people were both wounded and battle-weary and the-rowing (subject, nom) went (proceeded) slowly.

En Þórarinn sótti ákaft róðurinn og hans menn er þeir voru hvíldir og drógu skjótt eftir þeim Steinólfi og Kjallaki.
But Þórarinn undertook the-rowing fervently and his people (men) when they were rested and speedily drew after (gained on) them, Steinólf and Kjallakr.

Steinólfur bað þá ei undan róa að þeir hyrfu fyrir það aftur er eftir sóttu "því að vera kann að þeir nenni eigi að bíða hinna er eftir róa og mætti áður umskipti verða áður félagar þeirra kæmu eftir."
Steinólfr bade them not (ei, Z2) to row away (so) that they turned back around before (ie in the face of) that (ship?) which followed behind “because (it) can be that they are not willing (inclined) to wait for those-others (ie their comrades) who row behind and a “decisive-turn” might already happen before their comrades come after (them). (ie our best chance of victory is to fight this lot before the others arrive)

See Brian´s earlier note to Gull-Thoris Saga 12 C + 13 A:

<umskipti> Baetke has ‘entscheidende Wendung, Entscheidung
(zwischen zwei Gegnern)’, more or less ‘decisive turn,
tipping point, decision’.