00:34 Jul 28 

Yes David, you had me - I am looking for the Catalan term, but with Danish-Catalan direct resources being scarce, I am forced to look around! In any case I think Pernille's comment just above yours really sets me into the good direction. Now I have to find something just as archaic in Catalan...

Thanks everyone!

22:33 Jul 27 

Læster - En læst er en meget gammel betegnelse for enten en tørlast mellem 1,3 og 3,1 kubikmeter tørlast eller i mere moderne tid en skibslæst på 150 kubikfod med en ...
flaaden500.dk/Læster.49.aspx -

06b8-Temaartikler.html - En kommercelæst eller skibslæst var rummål for skibets lasteevne og drægtighed. I 1800-årene var 1 kommercelæst = 150 kubikfod = 2.600 kg, men blev ved lov ...
www.museum-sonderjylland.dk/.../06b8-Temaartikler.html -

[PDF] Sandskuden »Jomfru Marie« af Klitmøller - : PDF/Adobe Acrobat - Vista
En skibslæst. (kommercelæst) var dengang fastsat til 150 kubikfod svarende til en normalvægt på 2600 kg. Den mindste af de. 9 skuder var på 6 læster, ...
www.thistedmuseum.dk/.../Krogh-Jensen, G. Sandskuden Jomf...�l... -

Tonnage og skibsmåling - en oversigt - I Aakjærs beskrivelse af især middelalderlige mål angives en skibslæst i 1700 at være på de 4.000 pund = 2 tons og omregnet efter et ladningseksempel, ...
www.jmarcussen.dk/maritim/mart/.../tonnage.html -

10:52 Jul 27 

Here's what I found in an 18th century Danish Marine Dictionary (Dansk Søe Ord-bog by Georg Albrecht Koefoed - and yes, he did use this awful punctuation in the Danish title!):

"Læst - et Maal som Skibes Last beregnes udi, den tages almindelig for 4000 [symbol for "pund à 500 g") Vægt og bliver et hvert Handel Skib Ammet til hvormange læster det kan føre;
Laste ou leste, une mesure de deux Tonneau[x] ou de 4000 livres;
A last, a weight of 4000 pounds , or two tuns."
This book is a bit of a museum piece, so this is the first time I've had a chance to use it. But as Blixen often reached into the past for inspiration, I would personally stick to 'last' as these terms seem to have been interchangeable at this point in history.

08:02 Jul 26 

According to Chambers English Dictionary, a last is "a load, cargo; a varying weight, generally about 4,000 lb". Etymology is given as from OE "hlæst", which interestingly enough is the same as for "læst" in ODS. So I think it's a safe bet to say that læst/-er = last/-s. Why "ti/tolv læster" has been translated as "five lastages" is something I don't understand. The author seems to using "læst" as a measure of size/weight - "lastage" is a process (modern English "lading") or a hold for "lasts".
Karin Blixen has chosen to use the old Danish term, so as the translator of a literary work, I would argue that, if the target language has an equivalent old term, then one should use that. There should not be any question of updating it for a contemporary audience - that's the reader's responsibility.
But is this your problem, Maria? Or are you translating into Spanish/Catalan and looking for an equivalent term? Can't help with that I'm afraid :D