Η επιβίβαση οχημάτων γίνεται από τον καταπέλτη.

Because it depends on η επιβίβαση.

Η επιβίβαση οχημάτων literally means the boarding of vehicles.
This is a very common Greek pattern:

• η επιβίβαση επιβατών = the boarding of passengers
• η φόρτωση εμπορευμάτων = the loading of goods

So οχημάτων is genitive plural of όχημα and shows what is being boarded.

Because the phrase is general: vehicle boarding or the boarding of vehicles.

Greek often leaves out the article in this kind of genitive phrase when speaking generally:

• η πώληση εισιτηρίων = ticket sales / the sale of tickets
• η μεταφορά εμπορευμάτων = transport of goods

If you said η επιβίβαση των οχημάτων, that would usually sound more specific, like the boarding of the vehicles—particular vehicles already known from the context.

Επιβίβαση is a noun meaning boarding or embarkation.

It comes from the verb επιβιβάζω / επιβιβάζομαι, related to getting onto a vehicle, ship, plane, etc.

So:

• η επιβίβαση οχημάτων = boarding of vehicles
• η επιβίβαση επιβατών = boarding of passengers

In signs and announcements, Greek often prefers this kind of noun phrase instead of a full verbal sentence.

Here γίνεται means something like:

• takes place
• is carried out
• happens

The verb is γίνομαι, which very often means to happen, to take place, or to become, depending on context.

So Η επιβίβαση οχημάτων γίνεται... means:

• Vehicle boarding takes place...
• The boarding of vehicles is done...

This is a very natural formal style in Greek.

Because the subject is η επιβίβαση, which is singular.

Even though οχημάτων is plural in meaning, it is not the subject. It is just a genitive complement of επιβίβαση.

So the structure is:

• Η επιβίβαση = subject, singular
• οχημάτων = genitive, dependent on the noun
• γίνεται = singular verb matching η επιβίβαση

Not exactly in a strict grammatical sense, but it feels passive in English.

Greek uses γίνεται very often in official or informational language to give a neutral, process-focused meaning:

• Η επιβίβαση οχημάτων γίνεται από τον καταπέλτη.

This does not focus on who performs the action. It focuses on how/where the process happens.

A more directly verbal version could be something like:

• Τα οχήματα επιβιβάζονται από τον καταπέλτη.
  = Vehicles board / are loaded via the ramp.

So the original sentence is more formal and sign-like.

The preposition από takes the accusative, and here it means something like:

• from
• through
• via

So:

• από τον καταπέλτη = through/via the ramp

In this context, καταπέλτης is not a catapult. On ferries and ships, it means the loading ramp or gangway/ramp used for vehicles.

So the phrase tells you the access point or route for boarding.

Because καταπέλτης is masculine singular, and από takes the accusative.

The forms are:

• nominative: ο καταπέλτης
• accusative: τον καταπέλτη

Since the sentence uses από + accusative, you get:

• από τον καταπέλτη

Very often yes, but not always in a simple literal English way.

In this sentence, από is best understood as via or through, because the idea is the point or route of access.

Compare:

• Έρχεται από την Αθήνα. = He is coming from Athens.
• Μπείτε από την πίσω πόρτα. = Enter through the back door.
• Η επιβίβαση γίνεται από τον καταπέλτη. = Boarding takes place via the ramp.

So you should learn από as a flexible preposition whose exact English translation depends on context.

Greek uses the definite article much more often than English.

So Η επιβίβαση οχημάτων is perfectly natural even where English might say just:

• Vehicle boarding
• Boarding of vehicles

Greek often uses the article with abstract nouns, official notices, and general procedures.

Yes. Greek word order is more flexible than English.

The neutral order here is:

• Η επιβίβαση οχημάτων γίνεται από τον καταπέλτη.

But you could also see:

• Από τον καταπέλτη γίνεται η επιβίβαση οχημάτων.

That would put more emphasis on από τον καταπέλτη.

The original version is straightforward and natural for a notice or announcement.

The dictionary form is όχημα = vehicle.

It is a neuter noun, and its plural genitive is οχημάτων.

A quick pattern:

• singular: το όχημα
• plural: τα οχήματα
• genitive plural: των οχημάτων

In the sentence, you see the genitive plural without the article:

• οχημάτων

This is a useful pattern because many neuter nouns in -μα behave similarly.

You might hear it, but it sounds especially like formal, official, or sign/announcement Greek.

A more conversational version might be closer to:

• Τα οχήματα μπαίνουν από τον καταπέλτη.
• Η φόρτωση των οχημάτων γίνεται από τον καταπέλτη.

But on a ferry sign, in instructions, or in a public announcement, the original sentence is very natural.

From the context, a native speaker would understand it as the ship’s ramp for loading/unloading vehicles.

This is important because the basic dictionary meaning of καταπέλτης can also be catapult, but that is clearly not what is meant here.

In transport and ferry contexts, the meaning is specialized:

• καταπέλτης = loading ramp / ferry ramp

So context is doing a lot of work here.