I went to the Counting House, but I did not find any sea charts.I only found some books.
Are they anything like scrolls or something?Without them I can't go to that island(can't remember its name).

You have to get the charts from the sea captain, either kill him or pickpocket him.

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[This message has been edited by Gunthar (edited August 04, 2000).]

Or you can clear his bar tab at the Blushing Mermaid and get them that way, you have to get this option through the correct dialogue though and I can't remember off the top of my head what it is.

1.I went to blushing mermaid, I searched everything, I talked to everyone but I didn't get any sea charts.

2.Who is the sea captain and where can I find him?

The captain is in the counting house in the north east area of Baldur's Gate, he's upstairs and through dialogue you can learn of his bar tab at the Blushing Mermaid, if you pay this for him then return to him he'll give you the sea charts.
BY the way his tab at the bar is 900GP.