A Ship for Isabela is an Act 2 companion quest for Isabela in Dragon Age II.
Acquisition
Finding a Ship in a Bottle in Smuggler's Cut during Blackpowder Courtesy will trigger the quest.
Walkthrough
Head to the Hanged Man in Lowtown to give it Isabela.
There may be a brief cutscene with Isabela approached at the bar by a man with a very bad pickup line. If you have completed a romance with a character other than Isabela, she will comment on it. Allowing her to make the joke will result in 
Isabela: friendship (+5). Refusing will result in 
Isabela: rivalry (+5). This is separate from A Ship for Isabela and may also occur before Questioning Beliefs (Isabela Act 2), depending on which order you complete the quests and the romance.
The following dialogue options are available:
- "It reminded me of you."
- "Cute?"
- "It's not cute."
- "The best thing is below decks." (Flirt)
Result
- On friendship path: Isabela: friendship (+10) (all dialogue options)
- On rivalry path:
Isabela: rivalry (+10) (all dialogue options) - +250 XP