Cockpiten i havkajakken er tørr.

Because cockpiten is the definite singular form of en cockpit.

• en cockpit = a cockpit
• cockpiten = the cockpit

In Norwegian, definiteness is often shown by adding an ending to the noun, instead of using a separate word like English the.

Norwegian usually writes compound nouns as one word.

So:

• hav = sea
• kajakk = kayak
• havkajakk = sea kayak

Then havkajakken is the definite form:

• en havkajakk = a sea kayak
• havkajakken = the sea kayak

This one-word spelling is very normal in Norwegian.

For the same reason that cockpit becomes cockpiten: the noun is in the definite singular.

• en havkajakk = a sea kayak
• havkajakken = the sea kayak

The ending -en is very common for definite singular nouns of the common gender.

So in this sentence, both nouns are definite:

• Cockpiten = the cockpit
• havkajakken = the sea kayak

Norwegian often prefers a structure like the cockpit in the sea kayak rather than a possessive structure.

So:

• Cockpiten i havkajakken = literally the cockpit in the sea kayak

A more directly possessive version would be something like:

• havkajakkens cockpit

That is possible, but it can sound more formal or less natural in everyday usage. The version with i is a very natural way to identify which cockpit is being talked about.

i means in or inside. Here it makes sense because the cockpit is understood as a space/opening in the kayak.

• i havkajakken = in the sea kayak

If you used på, that would mean on the sea kayak, which would suggest something located on top of it rather than inside it. So i is the natural choice here.

Because adjectives in Norwegian agree with the noun they describe.

Here, the noun is cockpiten, which is:

• singular
• common gender
• definite

When an adjective comes after the verb er (as in is dry), it is a predicative adjective. Predicative adjectives agree mainly in gender and number, not by taking a special definite form.

So:

• common gender singular: tørr
• neuter singular: tørt
• plural: tørre

That is why the sentence has:

• Cockpiten ... er tørr

not tørt or tørre.

The structure is:

• Cockpiten i havkajakken = subject
• er = verb
• tørr = subject complement / predicate adjective

So the whole sentence follows a very common pattern:

[subject] + [er] + [adjective]

Just like in English:

• The cockpit in the sea kayak is dry.

The phrase i havkajakken belongs with cockpiten and helps identify which cockpit is meant.

Because Norwegian usually builds the into the noun itself.

In this sentence:

• cockpiten already means the cockpit
• havkajakken already means the sea kayak

So Norwegian does not need separate words like English the in these places.

Cockpit is understandable and used, especially because it is an international loanword. But in kayaking, a more specifically Norwegian term is often sittebrønn.

So you may also encounter:

• Sittebrønnen i havkajakken er tørr.

That said, the original sentence is still clear and natural enough, especially for learners or in more general language.