SCORPENE CLASS : The diesel-electric submarines are being built at the state-run Mazgaon docks in Mumbai; they are expected to be inducted into the Navy by 2018, about four years later than planned. The project has also over-shot the budget by nearly Rs. 5,000 crore and is expected to cost about Rs. 23,000 crore. ''One (Scorpene) submarine will be delivered every nine months,''