Sindhudurg was built in order to control attacks by Portuguese and Siddhis on the coastal areas of the Maratha Empire. This fort is the witness of Shivaji's Navy which was later led by Kanhoji Angre in times of Shivaji's grandson Shahu I, and came to glory. Also Shivaji built the forts of Colaba and Underi to control the activities of the Siddhis in Arabian Sea. At the time of Underi's construction British opposed a lot and stood with their warships in the sea to obstacle the material being supplied for the construction of the fort. But for their surprise the material required for construction was being supplied with the help of small boats in night.