For the dredging of the sludge, we needed a floating object that would collect and dump the waste. it would be very difficult to mount a digger directly on the boat since it would affect the stability of the system. if the dredger is operated at the centre of the boat, then the boat will acquire more stability. hence, we thought of using a two hull boat that has a hole in the centre. another problem we faced is the type of scoop to collect the sludge. unlike normal scoops that are used for digging on lands, we have to use some other mechanism for the better collection of sludge as well as the overall system stability. grab mechanism is found to be best in case of underwater operations. we designed our own grab mechanism subjected to our needs.