The Sandhayak-class survey ships are a series of eight vessels built by Garden Reach Shipbuilders and Engineers (GRSE), Kolkata and Goa Shipyard, Ltd., Vasco for the Indian Navy. While Sandhayak, Investigator, Nirdeshak, Nirupak were built in GRSE; Sarveshak, Jamuna, Darshak, Sutlej were built by Goa Shipyard. The vessels equipped with four survey motor boats, two small boats and are powered by two diesel engines with a top speed of 16 knots (30 km/h; 18 mph). They have a helicopter deck and are also armed with a Bofors 40 mm/60 gun mount for self-defense.