Судя по швартовому тросу, паромная переправа завершена.

Судя по means judging by, judging from, or based on.

It introduces the evidence for a conclusion:

• Судя по погоде, будет дождь. — Judging by the weather, it will rain.
• Судя по его голосу, он устал. — Judging by his voice, he is tired.

Grammatically, судя comes from the verb судить, but in modern Russian судя по is best learned as a fixed expression.

In your sentence, судя по швартовому тросу means that the speaker is drawing a conclusion from the mooring rope.

Because судя по requires the dative case.

The dictionary form is:

• швартовый трос — nominative singular

After судя по, it changes to dative:

• швартовому тросу

Breakdown:

• швартовый → швартовому
• трос → тросу

So this is a case-governed change, not a different word.

Швартовый трос is a mooring rope / mooring line / mooring cable.

• швартовый relates to mooring or docking
• трос is a rope-like cable, often heavier or more technical than a simple верёвка

So трос often sounds stronger, thicker, or more nautical/industrial than just rope.

Depending on context, English could translate it as:

• mooring rope
• mooring line
• mooring cable

Not necessarily. Паромная переправа usually means the ferry crossing, ferry service, or ferry route, rather than just the boat.

Breakdown:

• паромная — ferry-related
• переправа — crossing, transport crossing, passage across water

So паромная переправа is the crossing operation or service that takes people/vehicles across, not simply the vessel.

That is why завершена here is understood as something like finished / concluded / over with reference to the service or crossing operation.

Because завершена is the short form, used as the predicate: is completed / is finished.

Compare:

• Переправа завершена. — The crossing is finished.
• завершённая переправа — a completed crossing

In Russian, the short form is very common when you are saying what state something is in.

Also, завершена is feminine singular because переправа is feminine:

• masculine: завершён
• feminine: завершена
• neuter: завершено
• plural: завершены

So the form agrees with переправа.

Yes, in a sense.

Russian normally does not use a present-tense form of to be in sentences like this. So:

• Паромная переправа завершена.

literally has no separate word for is, but it means:

• The ferry crossing is completed / finished.

This is completely normal Russian.

If you wanted past or future, you would use forms of быть:

• Паромная переправа была завершена. — was completed
• Паромная переправа будет завершена. — will be completed

Because судя по швартовому тросу functions as an introductory phrase.

It does not form the main statement itself; instead, it tells you the basis for the speaker’s conclusion. Russian typically separates this kind of phrase with a comma.

So the structure is:

• Судя по швартовому тросу, — judging by the mooring rope,
• паромная переправа завершена. — the ferry crossing is finished.

This punctuation is standard.

Yes. Russian word order is flexible.

You could also say:

• Паромная переправа завершена, судя по швартовому тросу.

That would still be understandable. The difference is mainly emphasis:

• Судя по швартовому тросу, ... puts the evidence first
• ..., судя по швартовому тросу makes the evidence sound more like an added comment

The version with судя по... first is very natural if the speaker wants to foreground how they know.

No. It is often followed by a noun phrase, but not only that.

Common patterns include:

• судя по + noun
  • Судя по карте, мы рядом.
• судя по всему
  • Судя по всему, он не придёт. — Apparently / judging by everything, he won’t come.
• судя по тому, что...
  • Судя по тому, что он сказал, он согласен.
• судя по тому, как...
  • Судя по тому, как она говорит, она волнуется.

So it is a very useful expression for making inferences.

It is grammatical and natural enough, but it sounds somewhat formal or descriptive, especially because of words like швартовый трос and завершена.

In everyday speech, a person might also say something more conversational, such as:

• Похоже, переправа уже закончилась.
• Переправа уже закрыта.

But if the context is nautical, technical, or descriptive, Судя по швартовому тросу, паромная переправа завершена is perfectly plausible. It sounds like someone is observing a situation and drawing a conclusion from visible evidence.