The Sandhayak-class survey vessels are a series of four survey vessel<nowiki/>s being built by Garden Reach Shipbuilders and Engineers (GRSE), Kolkata for the Indian Navy. The first vessel was commissioned in 2021. The primary role of the vessels would be to conduct coastal and deep-water hydrographic survey of ports, navigational channels, Exclusive Economic Zones and collection of oceanographic data for defence. Their secondary role would be to perform search & rescue, ocean research and function as hospital ships for casualties.
In April 2016, the Indian Navy issued a request for proposal to six shipyards, four public and two private, for the construction of four large survey vessels. In September 2017, Garden Reach Shipbuilders and Engineers (GRSE) emerged as the lowest bidder with a bid of , beating L&T Shipbuilding by . The contract for design, construction and supply of the vessels was awarded to GRSE by the Ministry of Defence on 30 October 2018. The first ship is expected to be delivered within 36 months from the date of signing the contract.
The ships have a displacement of and a length of . They have a cruising speed of with a maximum speed of and an operating range of at a speed of . The ships have a complement of 231 and are equipped with hydrographic sensor equipment and a hangar which can accommodate one advanced light helicopter. In the secondary role, the ships can be fitted with a CRN 91 naval gun. In addition, the vessels will follow MARPOL (marine pollution) Standards of the International Maritime Organisation and will be built per Classification Society Rules and Naval Ship Regulations.
The keel of the first ship Sandhayak, named after its predecessor , was laid down on 8 November 2019 and launched on 5 December 2021. It was expected to be commissioned by 2023, the boat was commissioned on 3 February 2024.
The second vessel of the class, Nirdeshak , was laid on 1 December 2020 and was subsequently launched on 26 May 2022. The ship was delivered to the Indian Navy on 8 October 2024. The ship was commissioned on 18 December 2024.
The third ship, Ikshak, was laid down on 6 August 2021 and launched on 26 November 2022. The ship was handed to the Indian Navy on 14 August 2025.
Sanshodhak was delivered to the Indian Navy on 30 March 2026 along with and .