Araç güvertesi doldu.

Because araç güvertesi is a Turkish noun compound.

In this kind of structure, the second noun usually takes the 3rd person possessive suffix. So:

• güverte = deck
• güverte-si = its deck

So araç güvertesi literally looks something like vehicle its-deck, but in natural English it simply means vehicle deck.

This is a very common Turkish pattern:

• otobüs durağı = bus stop
• yatak odası = bedroom
• okul kapısı = school gate

So araç güvertesi is the normal way to say vehicle deck.

Yes, but not in exactly the same way as English possession.

It is an indefinite noun compound in Turkish. The first noun, araç, functions like a classifier or category word, and the second noun gets the possessive ending:

• araç = vehicle
• güvertesi = deck + compound suffix

This does not necessarily mean that one specific vehicle owns the deck. It just means the deck related to vehicles or the vehicle deck.

Compare:

• arabanın kapısı = the car’s door / the door of the car
  
  • this is a regular possessive phrase with genitive
• araç kapısı would not usually mean the same thing in the same way

So here, araç güvertesi is best understood as a set phrase meaning vehicle deck.

Doldu comes from the verb dolmak, which means to become full or to fill up.

Breakdown:

• dol- = verb root
• -du = past tense suffix

So:

• dolmak = to become full
• doldu = became full / filled up

The sentence is in the simple past tense, so it describes a completed event.

Because dolmak and doldurmak are different verbs.

• dolmak = to become full, to fill up
  
  • intransitive
• doldurmak = to fill something
  
  • transitive

So:

• Araç güvertesi doldu. = The vehicle deck filled up / became full.
• Birisi araç güvertesini doldurdu. = Someone filled the vehicle deck.

In your sentence, the deck itself is undergoing the change, so Turkish uses dolmak, not doldurmak.

Turkish does not have articles like the or a/an.

Whether something is definite or indefinite is understood from context, word order, and grammar.

So Araç güvertesi doldu can be translated naturally as:

• The vehicle deck filled up
• or sometimes A vehicle deck filled up

In practice, context usually makes the the best English translation here.

Yes.

The structure is:

• Araç güvertesi = subject
• doldu = verb

So the sentence follows the common Turkish pattern subject + verb.

The verb is in 3rd person singular, which matches the singular subject araç güvertesi.

Yes, but it means something a little different.

• Araç güvertesi doldu. = The vehicle deck became full / filled up.
• Araç güvertesi dolu. = The vehicle deck is full.

So:

• doldu focuses on the change/event
• dolu describes the state/result

This is an important distinction in Turkish.

The Turkish simple past tense is often shown as -DI, but that is just a dictionary-style pattern. In actual use, the vowel and consonant change according to sound harmony.

Here:

• the verb stem is dol-
• after this stem, the past suffix becomes -du

So:

• geldi
• bitti
• okudu
• doldu

The exact form changes because of vowel harmony and consonant patterns.

Araç güvertesi doldu is a normal, neutral word order.

Turkish often puts the verb at the end, and that is what happens here.

You may also hear different word orders for emphasis, but the basic version is:

• Araç güvertesi doldu.

For example, moving things around can change what is emphasized, but this simple order is the most straightforward and natural if you are just stating the fact.

It is pronounced approximately like gyu-ver-te-si.

A few useful notes:

• ü is a front rounded vowel, somewhat like the u sound in French tu or German über
• güverte has stress that is usually fairly light and even compared with English
• the final -si is clearly pronounced

So the whole phrase araç güvertesi should be spoken smoothly, with güvertesi treated as one word.