The simple past tense of sink is sank: “The boat sank yesterday.” The past participle is sunk, used with a helping verb: “The boat has sunk” or “The boat was sunk.” Sunken is usually an adjective before a noun, as in “a sunken ship,” although usage depends on the sentence.
Key Facts
Sink is the present-tense and infinitive form.
Sank is the standard simple past form.
Sunk is the standard past participle.
Has sunk, had sunk, and was sunk are correct constructions.
Sunken commonly modifies a noun directly, as in “sunken eyes.”
“The ship has sank” is nonstandard in edited modern English.
What Is the Past Tense of Sink?
The past tense of sink is sank, not sunk. Use sank when the verb describes one completed event in the past without a perfect-tense auxiliary: “The stone sank,” “The temperature sank,” and “The company sank into debt.”
The complete principal parts are:
| Verb form | Word | Example |
|---|---|---|
| Base form | sink | Ships sink in deep water. |
| Simple past | sank | The ferry sank on Monday. |
| Past participle | sunk | The ferry has sunk. |
| Present participle | sinking | The ferry is sinking. |
| Adjective | sunken | Divers found a sunken ferry. |
English calls sink an irregular verb because it does not form the past with -ed. The vowel changes from i to a in the simple past and to u in the participle. Similar patterns appear in sing, sang, sung and drink, drank, drunk, although every irregular verb must still be learned individually.
When Should You Use Sank?
Use sank for a completed past event when no auxiliary verb comes directly before the verb. The sentence may contain other verbs, but sank itself carries the past-tense marking.
Examples include:
- The canoe sank near the riverbank.
- The sun sank below the horizon.
- Her confidence sank after the interview.
- The price sank by 15% in June.
- The stone sank through the soft mud.
The same rule applies to statements, negatives, and questions. In negatives and questions, did carries the past tense, so the main verb returns to sink.
| Sentence type | Correct example | Why |
|---|---|---|
| Statement | The raft sank quickly. | Sank carries past tense. |
| Negative | The raft did not sink. | Did carries past tense. |
| Question | Did the raft sink? | Did requires the base form. |
| Contrast | The raft sank, but the buoy floated. | Both events occurred in the past. |
A frequent error is “Did the boat sank?” The correct sentence is “Did the boat sink?” English normally marks past tense only once in this structure.
When Should You Use Sunk?
Use sunk as the past participle after has, have, or had, and in passive constructions after forms of be. The helping verb establishes the grammatical structure, while sunk identifies the verb’s completed or passive form.
Examples of perfect constructions:
- The ship has sunk.
- Two barges have sunk this year.
- The wreck had sunk before rescuers arrived.
- The bad news has sunk her hopes of promotion.
Examples of passive constructions:
- The vessel was sunk by a naval mine.
- Three ships were sunk during the battle.
- The damaged platform has been sunk below the surface.
The distinction is structural rather than merely chronological. Both sank and sunk can describe an event that happened before now, but sunk needs the appropriate auxiliary in standard modern English.
How Do Perfect Tenses Change the Verb?
Perfect tenses use a form of have plus the past participle sunk. The choice between has, have, and had depends on the subject and the time relationship.
| Tense | Structure | Correct example |
|---|---|---|
| Present perfect | has/have + sunk | The ferry has sunk. |
| Past perfect | had + sunk | The ferry had sunk before dawn. |
| Future perfect | will have + sunk | The ferry will have sunk by noon. |
| Modal perfect | could have + sunk | The ferry could have sunk in the storm. |
The sentence “The ferry had sank” fails because had already requires a past participle. The correct form is “The ferry had sunk.”
Is “Was Sunk” Correct?
Was sunk is correct when the sentence uses the passive voice. In “The submarine was sunk,” the submarine receives the action, while the person, weapon, or event causing the action may appear after by.
Compare these sentences:
- Active: The torpedo sank the submarine.
- Passive: The submarine was sunk by the torpedo.
- Perfect active: The torpedo has sunk the submarine.
- Simple past active: The torpedo sank the submarine.
| Construction | Subject’s role | Example |
|---|---|---|
| Active simple past | Performs the action | The storm sank the boat. |
| Passive simple past | Receives the action | The boat was sunk by the storm. |
| Active present perfect | Performs completed action | The storm has sunk the boat. |
| Passive present perfect | Receives completed action | The boat has been sunk. |
A passive sentence does not use sank after was, were, or been. The form after the auxiliary must be the participle: was sunk, not was sank.
Is Sunken the Past Tense of Sink?
Sunken is not the standard simple past tense of sink. It is usually an adjective placed before a noun, although it can also appear after a linking verb in established descriptions such as “The eyes looked sunken.”
Common examples include:
- a sunken ship
- sunken cheeks
- a sunken garden
- sunken treasure
- sunken costs
The choice between sunk and sunken can depend on position and meaning.
| Form | Typical grammar | Example | Meaning |
|---|---|---|---|
| sank | Simple past | The ship sank. | Past event |
| sunk | Past participle | The ship has sunk. | Completed event |
| sunk | Predicate adjective | We are sunk. | In serious trouble |
| sunken | Noun modifier | A sunken ship was located. | Already below a surface |
| sunk | Fixed noun modifier | sunk costs | Costs already incurred |
The phrase sunk cost is standard, not sunken cost. In contrast, sunken treasure describes treasure located underwater. These are lexical conventions, so a mechanical “before a noun always means sunken” rule produces mistakes.
Sank vs Sunk: Which Form Fits the Sentence?
The correct choice depends mainly on the word immediately before the verb and the role of the verb in the clause. Use sank for a standalone past action, sunk after a perfect-tense or passive auxiliary, and sunken when a descriptive adjective modifies a noun.
| Intended meaning | Correct form | Example |
|---|---|---|
| Completed event yesterday | sank | The canoe sank yesterday. |
| Completed event before now | has sunk | The canoe has sunk. |
| Earlier event before another past event | had sunk | The canoe had sunk before help arrived. |
| Passive event | was sunk | The canoe was sunk by debris. |
| Descriptive noun phrase | sunken | Divers found a sunken canoe. |
| Fixed financial expression | sunk | The sunk cost cannot be recovered. |
Can the “Go” Test Help?
The go substitution test can help identify the structure. If went fits, choose sank; if gone fits after a helping verb, choose sunk.
- The rock went under the water.
The rock sank under the water. - The rock has gone under the water.
The rock has sunk under the water.
The test is a memory aid, not a complete grammar rule. It cannot decide between sunk and sunken in phrases such as sunk costs and sunken eyes, because those choices depend on established adjective usage rather than verb tense alone.
What Are the Most Common Errors?
The most common errors occur when writers confuse simple past, past participle, and adjective forms. The fastest correction method is to identify whether did, has, have, had, was, were, or been already appears in the verb phrase.
| Incorrect sentence | Correct sentence | Explanation |
|---|---|---|
| The boat has sank. | The boat has sunk. | Has requires a participle. |
| The boat was sank. | The boat was sunk. | Passive voice requires a participle. |
| Did the boat sank? | Did the boat sink? | Did requires the base form. |
| The boat sunk yesterday. | The boat sank yesterday. | No auxiliary appears. |
| The company had sank deeply. | The company had sunk deeply. | Had requires a participle. |
| The sunk ship rested underwater. | The sunken ship rested underwater. | Sunken is the usual descriptive adjective. |
Three practitioner rules prevent most mistakes:
- Do not use two past markers. “Did sank” combines did and the past form unnecessarily.
- Do not treat every past-looking word alike. Sank marks simple past; sunk marks the participle.
- Check fixed phrases separately. “Sunk cost” is standard even though “sunken” often appears before nouns.
Can Sunk Be Used as the Simple Past?
Sunk can appear as a simple past form in historical writing, dialect speech, and some informal varieties, but sank is the safest standard choice in contemporary edited English. Writers may encounter older texts containing sentences such as “The ship sunk,” yet modern formal prose generally uses “The ship sank.”
The variation is part of the history of irregular verbs. English has long allowed competing forms in some contexts, and regional speech preserves alternatives that editorial standards do not always accept. That does not make sunk the best choice for a school assignment, report, examination, or professional publication.
Use these modern forms:
- Standard formal: The ship sank last night.
- Standard perfect: The ship has sunk.
- Standard passive: The ship was sunk.
- Historical or dialectal dialogue: The ship sunk last night, only when the voice or period requires it.
How Does Sink Work in Different Meanings?
Sink can describe downward movement, declining amounts, emotional deterioration, or deliberate submersion. The tense rule remains the same across these meanings, but the surrounding vocabulary changes.
| Meaning | Simple past example | Perfect or passive example |
|---|---|---|
| Move downward | The stone sank. | The stone has sunk. |
| Go below water | The raft sank. | The raft was sunk by the current. |
| Decline in value | Shares sank 8%. | Shares have sunk 8%. |
| Become discouraged | His spirits sank. | Her confidence had sunk. |
| Deliberately submerge | The navy sank the target. | The target was sunk at sea. |
The verb may be transitive or intransitive. An intransitive use has no direct object: “The boat sank.” A transitive use takes an object: “The explosion sank the boat.” Both uses retain sank in the simple past and sunk in perfect or passive constructions.
How Should You Choose in a Real Sentence?
Apply this four-step process:
- Find the main verb phrase. Ignore nearby nouns and unrelated verbs.
- Check for an auxiliary. Look for did, has, have, had, was, were, or been.
- Choose the form. Use sink after did, sank alone in simple past, and sunk after perfect or passive auxiliaries.
- Check adjective placement. Use sunken for many physical descriptions and sunk in fixed terms such as sunk cost.
For example:
- “The anchor ___ at noon.” No auxiliary appears, so use sank.
- “The anchor has ___.” The auxiliary has appears, so use sunk.
- “The anchor was ___ by the chain.” The sentence is passive, so use sunk.
- “The divers saw a ___ anchor.” A descriptive noun modifier is needed, so sunken is likely.
FAQ About Sank, Sunk, and Sunken
Is “The ship sunk” grammatically correct?
In contemporary standard English, write “The ship sank.” The form sunk as a standalone simple past occurs in some dialects, informal speech, and older writing, but it is usually marked nonstandard in edited modern English. Use “The ship has sunk” when a perfect auxiliary is present.
Is “I have sank” or “I have sunk” correct?
“I have sunk” is correct. The auxiliary have must be followed by the past participle, and the past participle of sink is sunk. The simple past form sank works without have: “I sank the boat in the simulation.”
What is the past participle of sink?
The past participle of sink is sunk. It appears after has, have, or had, and in passive phrases after forms of be: “The water level has sunk,” “The ship was sunk,” and “The vessel had sunk before dawn.”
Should I write “sunken ship” or “sunk ship”?
Use sunken ship when describing a ship that lies underwater or below a surface. Sunk ship can be grammatically possible, especially in a technical or passive context, but sunken ship is the established descriptive phrase for a wreck or submerged vessel.
What is the past tense of “sink” in British English?
British and American standard English both use sank as the simple past and sunk as the past participle. Regional speakers may use sunk as a simple past form, but that variation does not change the safest formal rule: “The boat sank,” and “The boat has sunk.”
What is the difference between “sunk cost” and “sunken cost”?
Sunk cost is the standard economic term for money, time, or resources already spent and unrecoverable. Sunken cost is generally considered an error in that expression. Use sunken for many physical descriptions, such as sunken eyes or a sunken garden.
The Bottom Line
For sank vs sunk, whats the past tense of sink, the direct answer is sank. Write “The boat sank” for a completed past action, “The boat has sunk” for a perfect construction, and “The boat was sunk” for passive voice. Use sunken mainly as a descriptive adjective, while retaining fixed expressions such as sunk cost.
