> Þeir Steinþór gengu inn í Þingskálanes og drógu skipið úr
> naustinu.

> They, Steinghor (& co.), went in to the Thing’s shed and
> dragged the ship out of the boathouse.

Steinþór and his companions went in to Þingskálanes and
dragged the ship from the boathouse.

Þingskálanes is a ness, literally 'þing-hall-ness' or
'þing-hut-ness'.

> Þeir tóku bæði árar og þiljur úr skipinu og lögðu þar
> eftir á ísnum og svo klæði sín og vopn þau er þyngst voru.

> They took both oars and decks (?) out of the ship and set
> off there along to the ice and so their clothes and
> weapons which were heavy.

They took both oars and deck from the ship and left [them]
there on the ice, and similarly their outer clothing and
those weapons that were heaviest.

The singular <þilja> is a deck plank; the plural is simply
'deck'. You could translate <lögðu þar eftir> as either
‘laid [them] there’ or ‘left [them]there’: the <eftir> means
that these things were left behind, and the <lögðu>
specifies that this was done by laying them down on the ice.
Or you could expand the English to give the meaning but not
match the wording: ‘laid them on the ice and left them
there’. It doesn’t specifically say that it was just their
outer clothing that they left there, but clearly that must
be the case.

> Síðan drógu þeir skipið inn eftir firðinum og svo út yfir
> eiðið til Hofstaðavogs og allt út að skörinni.

> They then dragged the ship in along the firth and so out
> over the isthmus to Hofstadavog and out to the edge (Z
> says “rim”) of the ice.

After that they dragged the ship in along the fjord and so
out over the isthmus to Hofstaðavág and all the way out to
the edge [i.e., of the ice, where open water started].

> Síðan gengu þeir inn eftir klæðum sínum og öðrum föngum.

> They then went in for their clothes and other baggage.

After that they went in after their outer clothes and other
gear.

The stuff that they’d left behind with the ship.

> Og er þeir gengu inn aftur á Vigrafjörð sáu þeir að sex
> menn gengu innan úr Þingskálanesi og fóru mikinn út eftir
> ísnum og stefndu til Helgafells.

> And when they went in back to Vigrafiord, they saw that
> six men went in out of the Thing’s shed and went way out
> along the ice and went in the direction of Helgafell.

And when they went back in to Vigrafjörð, they saw that six
men were walking in from Þingskálanes and travelling rapidly
out along the ice and heading towards Helgafell.

See <mikill> Z5: the accus. sing. <mikinn> here functions
more or less as an adjective meaning 'fast'.

> Þeir Steinþór höfðu grun af að þar mundu fara
> Þorbrandssynir og mundu ætla til jólavistar til
> Helgafells.

> They, Steinthor (& the others), had a suspicion that there
> would go the sons of Thorbrand and they would intend to
> stay over at Yule at Helgafell.

Steinþór and his companions had a suspicion that Þorbrand’s
sons might be travelling there and might intend to stay at
the fjord at Helgafell over Yule.

> Tóku þeir Steinþór þá ferð mikla út eftir firðinum til
> klæða sinn og vopna þeirra sem þar voru.

> They, Steinthor (et al), started a long journey out along
> the firth to their clothes and their weapons which were
> there.

Then Steinþór and his company began a rapid [‘great’] trip
out along the fjord to their outer clothes and their weapons
that were there.

Here <taka> has the sense 'to set about, to begin (doing
something)'; a couple of the examples at Z2 are roughly
parallel. In plain English, they began to run.

> En þetta var, sem Steinþór gat, að þar voru
> Þorbrandssynir.

> And this was, as Steinghor observed, that they were
> Thorbrand’s sons.

And it [‘this’] was, as Steinþór guessed, that Þorbrand’s
sons were there.

> Og er þeir sáu að menn hljópu innan eftir firðinum þóttust
> þeir vita hverjir þar mundu vera og hugðu að Eyrbyggjar
> mundu vilja sækja fund þeirra.

> And when they saw that men ran in along the firth, they
> thought they know who would be there and thought that the
> Eyrbyggjars would want to seek their fight.

And when they saw that men ran from in along the fjord, they
thought that they knew who might be there and thought that
[the] Eyr-folk would want to seek an fight with them.

Remember that the <-an> suffix on directions gives a sense
of 'from that direction'.

> Tóku þeir þá og ferð mikla og stefndu til skersins og
> hugðu sér þar til viðurtöku og fórust þeir þá mjög svo í
> móti og komust þeir Þorbrandssynir í skerið.

> They, then, also started a long journey and went in the
> direction of the rocks in the sea and intended for
> themselves resistance there and they then perished much so
> against and they, Thorbrand’s sons, arrived at the rocks
> in the sea.

They then also began to run [‘began a rapid trip’] and
headed for the skerry and intended resistance there, and so
they ran almost directly at each other then, and Þorbrand’s
sons reached the skerry [first].

See <fara> Z11: <farast í móti> 'to march against one
another'. We also have <mjök> Z3 'almost, very nearly'.

> En er þeir Steinþór hljópu fram um skerið þá skaut
> Þorleifur kimbi spjóti í flokk þeirra og kom það á Bergþór
> Þorláksson miðjan og varð hann þegar óvígur.

> And when they, Steinthor (and the others), ran forward
> across the skerry, then Thorleifr Kimbi shot a spear at
> their party, and it landed on Bergthor Thorlakson in the
> middle and he became there at once “hors de combat. “

And when Steinþór and his men ran forward over the skerry,
Þorleif kimbi cast a spear into their company, and it hit
Bergþór Þorláksson [in] the middle, and he was at once unfit
to fight.

It’s also possible that <um> here is 'around, past'.

> Gekk hann inn á ísinn og lagðist þar niður en þeir
> Steinþór sóttu þá að skerinu en sumir fóru eftir vopnum
> þeirra.

> He then went in to the ice and laid down there, and they,
> Steinthor (and some others on Steinthor’s side), came then
> to the skerry and some went after their weapons.

He went in onto the ice and lay down there, and then
Steinþór and his men attacked the skerry, but some went
after their weapons.

> Þorbrandssynir vörðust vel og drengilega.

> Thorbrand’s sons defended themselves well and nobly.

Þorbrand’s sons defended themselves well and bravely.

> Höfðu þeir og vígi gott því að jakarnir voru hallir út af
> skerinu og voru ákaflega hálir.

> They also had a good fight because the ice flows were
> leaning out from the skerry and were exceedingly slippery.

They had a good vantage, for the ice floes were sloping out
from the skerry and were exceedingly slippery.

It’s the neuter noun <vígi> 'vantage ground, stronghold'.

> Tókust því seint áverkar með mönnum áður þeir komu aftur
> er vopnin sóttu.

> It began slowly, bodily injury between men, before they,
> who sought their weapons, came back.

Thus, men’s wounds occurred slowly before they who had gone
after the weapons came back.

> Þeir Steinþór sóttu sex að skerinu en Austmenn gengu í
> skotmál á ísinn frá skerinu.

> They, Steinthor (et al), attacked six at the skerry, and
> the Norwegians went in range of the ice from the skerry.

Steinþór and five of his companions attacked the skerry, but
the Eastmen went on the ice in [arrow] range of the skerry.

The word order is confusing: <sex> actually goes with <Þeir
Steinþór>, meaning that they were six altogether, including
Steinþór.

> Þeir höfðu boga og skutu á þá í skerið og varð þeim það
> skeinusamt.

> They had bows and shot at them in the skerry and they
> became exposed to being wounded.

They had bows and shot at those on the skerry, and that
exposed them [= those on the skerry] to being wounded.

Brian