The Vikings are not known for their gold ships. But
they have a few longships that can do a reasonable
job of rounding up doubloons, and the Donar is one
of them.
Her cannons are on the uninspiring side, even though
each of them gets to shoot twice. Her price is low
for a longship. What sets her apart is her decent
speed and her large cargo (no Viking has more except
for their S-speed tortoises). These, combined with
her cost, make her as good a gold-runner value as
you're going to find under the Northern Lights. The
Grendel is faster, but costs more; the Sleipner is
faster and cheaper, but has less cargo and is more
vulnerable.
I see the Donar operating without any crew, using
all her cargo spaces for gold. Some other longship
can carry the fighting crew and keep the enemy at
bay, while this two-master does the unusual task of
making a Viking admiral rich.