If you had sailed any slower, (in the past) the war would be over (now, in the present. We would be in a state of peace). If you had sailed any slower, (in the past) the war would have been over (by now. The war would have ended before now).
There is little practical difference in meaning.
24 hours after the war ended, we can say: The war is over.
The war has been over since yesterday.
Context is important. Please provide enough for us to be able to deal effectively with your question.
Your thread title should include all or part of the word/phrase being discussed.
If you just want to know the meaning of a word, try OneLook Dictionary Search first.