Solution:Shivaji, the Maratha ruler, erected all four naval forts mentioned: Suvarnadurg, Vijayadurg, Sindhudurg, and Kolaba. These forts were crucial components of Shivaji's naval strategy, aimed at establishing Maratha dominance along the Konkan coast and challenging other maritime powers, particularly the Siddi of Janjira and European traders.
Suvarnadurg and Vijayadurg, located in present-day Ratnagiri district, were formidable sea forts. Sindhudurg, built on an island near Malvan, was Shivaji's ambitious project to create an impregnable naval base.
Kolaba fort, near Mumbai, protected the northern Konkan coast. These forts demonstrate Shivaji's foresight in recognizing the importance of naval power and coastal defense in building and protecting the Maratha empire.