Breakdown of Kafbáturinn sigldi tíu sjómílur.
tíu
ten
sigla
to sail
kafbáturinn
the submarine
sjómílan
the nautical mile
Questions & Answers about Kafbáturinn sigldi tíu sjómílur.
Wait, doesn't sigla govern the dative case? Why is sjómílur in the accusative?
You are right that sigla takes the dative when referring to the vessel being steered (like sigla bátnum, sailing the boat). However, tíu sjómílur isn't the object being driven; it is the distance covered. Icelandic uses the bare accusative case without a preposition to show physical distance, regardless of the verb's normal case government.
How can I tell that sjómílur is in the accusative plural? It looks like the nominative.
You have to rely on the grammar rules! Sjómíla is a weak feminine noun. For weak feminine nouns, the nominative plural and accusative plural share the exact same -ur ending. You know it is accusative here solely because it is acting as the Accusative of Extent to measure a distance.
Why doesn't the number tíu decline to match the accusative plural noun?
In Icelandic, only the numbers 1 through 4 decline to match the gender and case of the noun they describe. Numbers from 5 onwards, including tíu, are indeclinable when used to count a noun, so it stays exactly the same.
What are the component parts of the word kafbáturinn?
It is a compound of kaf (a dive, or being submerged) and bátur (boat), plus the masculine definite article -inn attached to the end. Literally, it translates to the dive-boat.