Thanks for your help, Brian.
Grace

> Þá hljóp á útsynningr steinóði, en þar gekk í móti
> útfallsstraumr; gørði þá stórt á firðinum, sem þar kann
> opt verða; ...

> Then a violent south-westerly gale sprang up, and there
> went against (it) an ebb? current;

Yes.

> then the sea rose high (Z stórr, 1) in the firth, as there
> (one) knows often to happen, ...

This is <kunna> + infinitive, 'to be able', (10) in Zoëga:
'as can often happen there'.

> Víga-Óbívan spurði, hvárt hon vildi Anakin himingangara
> vita, at hann var faðir þessa tveggja barna, því at "Mik
> grunar, at hann haldi eigi fram at þjóna Falfaðni konungi,
> ok herja Írland, vissi hann sjálfan sik föður þessa írskra
> þjóðna.

> Slayer Obiwan asked, what

whether

> she wanted Anakinn skywalker to know, that he was father
> of these two children, because "I suspect that he would
> not support serving

Zoëga doesn't seem to have it, but CV s.v. <halda> (A.V.2.β)
has 'to hold on doing' as one meaning of <halda fram>. This
seems to make better sense here than 'support': 'that he
would not continue to serve'.

> King Palpatine, and to harry Ireland, he knew himself (to
> be) father of these Irish prince (and princess).

<Vissi> is subjunctive, so the natural modern English
translation is 'if he knew himself (to be)'. In very
old-fashioned usage one might say 'knew he himself (to be)'.

> En trúlegt er, at Falfaðinn konungr læti drepa þessi börn
> sem skjótlegast, ef honum þóttisk þetta má gøra, ok vissi
> hvar þau funnusk.

> But (it) is true

<Trúligr> isn't 'true'; that would be <sannr>. Here it's
(3) in Zoëga, 'credible'.

> that King Palpatine would have these children killed as
> quickly as possible if he thought this may

<Má> is 'can', though English sequence of tenses requires
'could'.

> happen and knew where they were to be found.

Brian
Fred and Grace Hatton
Hawley Pa