To dream of an accident at sea suggests potential problems with those who are close to you, or some kind of disappointment in love.
If water overwhelms you, you are likely to feel overwhelmed by emotions.
If this is the case, you need to assess how best to manage your feelings and put them into context.
If you are trying to save other people in a shipwreck, you need to think about what these people represent to you. For instance, if you are trying to save a baby, perhaps that represents an element in your waking life, such as unconditional love, or wonder and excitement, that you need to develop in your waking life to help you cope with your emotional response.
[1]