INS Darshak, the Indian Navy's hydrographic survey ship, is jointly with Sri Lankan Navy undertaking a joint hydrographic survey of Weligama Bay, the navy said in a tweet on Thursday.On a two-month deployment in the Sri Lankan waters, INS Darshak jointly with the Sri Lankan Navy is surveying the bay which was last studied in 1901.The Eastern Naval Command's (ENC) vessel left for Sri Lanka on March 3, 2017.INS Darshak is the Inian Navy's specialised survey ship, fitted with the latest state-of-the-art survey equipment like multi-beam system, side scan sonar and a fully automated digital surveying and processing system.In addition, the ship is also carrying an integral Chetak helicopter which would be extensively deployed during the course of the survey.It is the first of the Darshak class of ships and has a complement of 20 officers and 200 sailors and is presently commanded by Captain Peush Pawsey. The ship has the unique distinction of having undertaken various foreign cooperation surveys in the last few years in Mauritius, the Seychelles, Myanmar, Mozambique and Tanzania.