Depending on your experience with them, boats can represent riches, travel, isolation, danger, romance, or complete and utter frustration. Rowboats and canoes are often found on fairly placid lakes and streams. In dreams, they may be way out of context on the high seas, therefore implying a kind of broken peace. Normally, the setting of the boat says much about its symbolic meaning.Different types of boats may vary in meaning, but possible options include isolation, danger, escape, and romance.
Sailboats often appear in similar environs as rowboats, but tend to mean either riches or frustration: sailboats can be very affluent and romantic to the dreamer, however, being dead in the water for lack of wind is another option.
Power boats often show a sense of power, control, wealth, competition, or travel. Danger is not often a problem, except in cases of failed motors.
Sinking boats can reveal a fear of water, drowning, or incompetence. More often, they are a metaphor for feelings about a particular aspect of life. To determine this, look at who is on the boat or conspicuously absent from it. Also, see if the reason it is sinking, which may seem nonsensical, is available in the dream.
Is the boat one that you recognize? Is the general feeling one of happiness and leisure or one of fear and anxiety?