About

• INS Sindhuratna (S59) (Jewel of the Sea) is a Sindhughosh-class diesel-electric submarine of the Indian Navy.

How do diesel electric submarines work?

• Diesel electric submarines are powered by a diesel engine and an electric motor. 
• The diesel engine is used to generate electricity to power the electric motor, which turns the propeller. 
• The diesel engine only powers the electric motor when the submarine is submerged. 
• When the submarine is surfaced, the diesel engine powers the submarine directly. 
• Diesel electric submarines need to surface because the diesel engine needs to be able to breathe. 
• The diesel engine needs to take in air to combust the fuel. The air is taken in through a snorkel, which is a tube that sticks up out of the water when the submarine is surfaced.

Why in News?

The Navy’s Kilo-class submarine INS Sindhuratna which underwent a major upgrade in Russia reached Mumbai.