Ok er Hrafn hafði eigi lengi heima verit, þá fór hann í Vatnsfjörð at heimboði Þorvalds ok þá af honum stóðhross góð. 

And when Hrafn hadn't been long at home, then he went to Vatnsfiord to Thorvald's feast and then (got) from him a good stud-horse.

Þeir mæltu þá enn af nýju til vinfengis með sér. 

They then expressed  yet again a wish for friendship between them.     (Z. nýr 1: af nýju = anew, again)   (Z. mæla 3: m. til e-s, to express a wish for a thing)

Nökkuru síðar fór Þorvaldr á Eyri at heimboði Hrafns ok þá af honum góðar gjafir, ok var þá vinfengi þeira ít bezta.

Somewhat later, Thorvaldr went to Eyr to Hrafn's feast and then (got) from him good gifts, and then it was their best friendship.

12. Frá hvalreka ok frá Víga-Hauki ok Lofti.

Concerning a stranding of whales and concerning Viga-Hauk and Lofti.

Í Selárdal kom reyðarhvalr góðr ok mikill á land þat, er Ragnheiðr átti. 

In Selardale a good and large rorqual arrived to that land which Ragnheidr owned.     (for more info on rorqual, see https://en.wikipedia.org/wiki/Rorqual) 

Ok er Þorvaldr frá þat, fór hann í Selárdal ok bað Ragnheiði, at hon skyldi selja honum nökkurar vættir hvals, en Ragneiðr lét hann hafa tólf vættir hvals ok mælti, at hann skyldi gjalda henni jafnmikinn hval síðar, þá er ræki á fjörur hans. 

And when Thorvaldr heard of that, he went to Selardale and asked Ragnheidr that she should hand over to him some whale weight, and Ragneidr let him have 12 80-pounds of whale and said that he should repay her equally-as-much whale later, when (a whale) would be be driven to his beach.

Fyrir þann hval galt Þorvaldr aldri síðan. 

Thorvaldr never since paid back for that whale.

Ok er hann fór á brott ór Selárdal með hvalinn, gisti hann í Lokinhömrum, ok er hann var þar um nótt, þá var stolinn í brott sumr hvalrinn. 

And when he went away outside of Selardale with the whale (meat), he passed the night at Lokinghomrum (Shut-shape?), and when he was there during the night, some (of) the whale (meat) was stolen away.

Sá stuldr reyndist á hendr þingmanni Hrafns, þeim er bjó á Sléttanesi. 

The theft proved to be at the hands of Hrafn's liegeman, those (why the plural "þeim" if it's one man?) who lived at Slettaness (Plain-ness).

Ok er Hrafn varð þess varr, varð hann skjótr til ok bauð honum at gjalda fyrir þingmann sinn slíkt fé sem Þorvaldr vildi gert hafa fyrir hvaltökuna. 

And when Hrafn heard that, he became swift and asked him to repay for his liegeman such money as Thorvaldr would want to have judged for the whale-taking.      (Z. varr 1: verða e-s v., verða v. við e-t, to be aware of, learn, hear)

En Þorvaldr vildi eigi þiggja at Hrafni fébætr. 

But Thorvaldr didn't want to accept compensation from Hrafn.

Ok litlu síðar fór Þorvaldr ok rænti þann mann, er tekit hafði hvalinn, ok þaðan af tók Þorvaldr at ganga á hendr þingmönnum Hrafns at öðru hváru. 

And a little later, Thorvaldr went and robbed that man, who had taken the whale-meat, and from that time Thorvaldr began to submit to Hrafn's other liegemen nevertheless.     (Z. þaðan 3: þaðan af = þaðan frá = þaðan í frá = from that time)  (Z. ganga 15: g. á hönd (hendr) e-m, to submit to, give oneself up to, surrender to one) (Z. hvárr 3: at hváru = yet, nevertheless, however)

Maðr hét Haukr, er kallaðr var Víga-Haukr, sonr Orms Fornasonar. 

A man was named Haukr (Hawk), who was called Viga-Haukr (Battle-Hawk), a son of Orm Fornason's.

Hann var norðlenzkr at ætt. 

He was from the north of Iceland by heritage (i.e., his family was from the north of Iceland).

Hann kvángaðist vestr á Rauðasand ok fekk Hallberu, dóttur Markúss Gíslasonar, ok fór þangat vistfari til Lofts. 

He got married towards the west at Raudasand and married Hallbera, the daughter of Markus Gislason, and he changed his abode to Loft.   (I didn't find "vistfari"; however, CV has vista-fari, adj. changing one’s abode; fara vistafari.)

Þá er Gísli Markússon var fulltíða at aldri, þá beiddi hann Loft at gjalda fé þau, er hann hafði at varðveita, er þeir Markússynir áttu, ok Loftr galt féin af hendi, svá sem Gísli beiddi, bæði lönd ok lausa aura.  

Then when Gisli Markuson was full-grown, then he asked Loftr to repay the money, which he had kept, which the sons of Markus had, and Loftr repaid the money out of his hand, just as Gisli asked, both land and loose silver.