Submarines of the type Madchanu(fig.) were 51 meters long, 4.1 meters wide, and armed with four 450 millimeter torpedo tubes.

They could launch the initial torpedoes over a distance of 3,000 meters at a speed of 23 knots, though later types could reach distances of up to 8,000 meters at a speed of 30 knots, or a lesser distance at a higher speed.