Min søster vil gerne sejle igen i morgen, bare færgen går som planlagt.

Because søster is a common-gender singular noun in Danish.

• min = used with singular common-gender nouns
• mit = used with singular neuter nouns
• mine = used with plural nouns

So:

• min søster = my sister
• mit hus = my house
• mine søstre = my sisters

Vil gerne is a very common Danish way to express wanting to do something in a natural, polite-sounding way.

• vil on its own means want to / will
• gerne often adds the idea of gladly / willingly / would like to

Together, vil gerne often corresponds to English would like to or wants to.

So Min søster vil gerne sejle igen means something like My sister would like to sail/go by ferry again.

Using just vil can sometimes sound more direct or forceful than vil gerne.

Because vil is a modal verb, and after modal verbs in Danish, the next verb is normally in the bare infinitive form, without at.

So you get:

• vil sejle
• kan sejle
• skal sejle
• må sejle

Not:

• vil at sejle

This is similar to English, where we say will sail, not will to sail.

Not necessarily. In Danish, sejle can mean:

• to sail a boat
• to travel by boat or ferry
• to go by sea/water

In this sentence, because it mentions færgen later, the meaning is probably more like go by ferry / travel by boat, not that she herself is operating the vessel.

That is a normal position for an adverb like igen in this kind of sentence.

The structure is:

• vil gerne
  • infinitive verb + adverb/time phrase

So:

• vil gerne sejle igen i morgen

This sounds natural in Danish.
If you move igen, the emphasis can change slightly, but the given order is very normal.

In Danish, i morgen is the standard expression for tomorrow.

Even though i often means in, the whole phrase i morgen functions as a fixed time expression.

Compare:

• i dag = today
• i morgen = tomorrow
• i går = yesterday

So learners should usually treat i morgen as one unit.

Bare can mean different things depending on context.

Here, bare means something like:

• as long as
• provided that
• if only

So:

• bare færgen går som planlagt

means:

• as long as the ferry runs as planned
• provided the ferry goes as planned

This is a very common use of bare in spoken and written Danish.

Because Danish usually puts the definite article at the end of the noun as a suffix.

So:

• en færge = a ferry
• færgen = the ferry

This is one of the big differences from English.

Other examples:

• en bil = a car

• bilen = the car

• et hus = a house
• huset = the house

Yes, gå often means walk or go, but in Danish it is also used for transport services operating according to schedule.

So when people say:

• Bussen går klokken otte
• Toget går nu
• Færgen går som planlagt

they mean:

• the bus/train/ferry leaves
• runs
• is operating

So færgen går som planlagt is very natural Danish for the ferry is running as planned.

Literally, som planlagt means as planned.

It is a very common shortened expression. Danish often leaves out words that are understood from the context.

A fuller version might be something like:

• som det er planlagt

but in normal Danish that would usually sound heavier and less natural here.

So som planlagt is the idiomatic way to say as planned.

The comma marks the boundary between the main clause and the subordinate clause.

• Main clause: Min søster vil gerne sejle igen i morgen
• Subordinate clause: bare færgen går som planlagt

So the comma helps show that the second part depends on the first.

In modern Danish, you may sometimes see variation in comma use before subordinate clauses, but the comma here is completely normal and easy to understand.

Yes, it is a subordinate clause.

It has:

• a subject: færgen
• a verb: går

The word bare introduces the condition, a bit like if / provided that / as long as in English.

So the whole sentence is built like this:

• Main statement: My sister wants to go again tomorrow
• Condition: provided that the ferry runs as planned

Yes, that is grammatically correct, but it changes the tone a little.

• vil sejle = wants to sail / will sail
• vil gerne sejle = would like to sail / wants to sail

Adding gerne often makes the sentence sound more natural, softer, and more like a personal wish rather than a firm intention or decision.