VESSEL REVIEW | Sandhayak – First in new hydrographic survey ship class for Indian Navy

Indian state-owned shipbuilder Garden Reach Shipbuilders and Engineers (GRSE) recently handed over the lead ship of a new class of large hydrographic survey vessels ordered from the company by the Indian Navy.

INS Sandhayak is the first vessel in the Sandhayak-class, which were designed jointly by GRSE and the Indian Navy's own Warship Design Bureau with greater capabilities compared to a similarly named class of locally built hydrographic survey ships operated by the navy since 1981. Also, because of their greater dimensions, the newer Sandhayak-class ships are the largest survey vessels ever built in India.

As with their predecessors, the newer Sandhayak-class ships' primary roles include deep-water surveys of ports, coastal areas and navigational channels and collection of oceanographic and geophysical data in support of the activities of the Indian Ministry of Defence and civil agencies. The vessels will also be equipped to perform marine research and search and rescue (SAR) and to operate as a hospital ship during wartime and in the event of disasters.

Sandhayak has a length of 110 metres, a beam of 16 metres, a displacement of 3,300 tonnes, and space for 231 crewmembers as well as unmanned craft such as autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs). In addition to the unmanned vehicles, multibeam echosounders and a data acquisition and processing system are fitted for survey work. Other sensors include a GPS and a side-scan sonar.

Two diesel engines enable Sandhayak to reach a maximum speed of 18 knots and sail 6,500 nautical miles at a cruising speed of 16 knots. The extended endurance will permit operations up to India's extended continental shelf and the maritime limits of the country's exclusive economic zone.

Although designed for non-combat roles, the survey vessel is fitted with a CRN-91 30mm naval gun for self-defence. An aft flight deck and a hangar can meanwhile accommodate a light utility helicopter.

Sandhayak was built with greater than 80 per cent indigenous content in line with Prime Minister Narendra Modi's "Make in India" campaign that incentivises local manufacture. Sister vessels INS Nirdeshak, INS Ikshak, and INS Sanshodhak are in various stages of construction at the Kattupalli shipyard of GRSE sub-contractor Larsen and Toubro.