Mumbai: After a speedboat carrying officials and political workers to visit the Shivaji Memorial site in October capsized, killing one, the Maharashtra Maritime Board (MMB) is going to use a sonar device to check for rocks and other objects in the water that grazed the boat from below.MMB, which is investigating the incident, has been given 30 days by the state to finish the probe and submit a report, said Vikram Kumar, chief executive officer of MMB. The probe report is expected by November-end. On October 24, a private boat called ‘MRM1’ was carrying mostly political workers to the memorial site of Maratha king Shivaji, in the middle of the sea for a bhoomi puja function. It presumably hit a rock and capsized, killing a 35-year old Mumbai resident. Kumar said they have officially commenced the investigation jointly with the Directorate General of Shipping. “To know what hit the boat, we will use a sonar device or echo sounding. This will help us find the depth at which rocks are present on the stretch; whether there was just one rock or if it was a patch. The examination will be conducted at the same tide level when the accident occurred.” Senior MMB officials said the water had receded at the time of the accident as the tide was low. A senior MMB official said they are also going check whether the route taken by the boat was correct or if it was a “short-cut”. “We are going to study the maps of the water near Prongs Reef to ascertain if there is a channel for smaller boats.” Officials said they will also interview the passengers who were on the boat to chalk out the sequence of events. They have still not interviewed the master of the boat, Ruchit Sakharkar. “We have not interviewed Shakhrakar as he is still in shock, but we will visit him soon. His statement is very important for the investigation,” Kumar said.