The Brennan torpedo was the first effective guided weapon. Introduced into service in 1887, the Brennan was launched from a shore-side fort and powered by a steam engine which pulled wire off drums in the torpedo. As the wire was pulled in, the drums rotated so powering the propellors that drove it through the water.
Brennan torpedo sites were used to protect the entrances of naval ports. Its major advantages were that if the target manoeuvred, the torpedo could be steered to intercept after launch, by tracking a mast showing above the water. It also carried a large warhead that would strike below the heavy armoured belt. At least 8 Brennan sites have been identified, 5 in the UK and Ireland, 2 in Malta and one in Hong Kong.
Brennan torpedoes had a speed of about 26 knots, well in excess of the speed on the battleships of the time, and a range of 2000 yards. They carried a warhead of 230 (later 364) lbs wet guncotton.
Some details of the Brennan are still secret. The depth mechanism is sealed, and there are no drawings to show how it worked, so the movie shows one of the techniques available at the time. The single remaining original Brennan can be seen at the Royal Engineers museum, Chatham, England.
Animation of 16 inch torpedo, Whitehead design, built by the Royal Laboratories in about 1876. This torpedo has a warhead of 116 lbs (52.5 Kg) wet guncotton, a compressed air compound oscillating engine giving a speed of 9 knots and a range of 1,200 yards (1.1 Km). The animation shows the desk launch carriage that was used when HMS SHAH fired a 16 inch torpedo at the Peruvian armoured turret ship Huascar in 1877. Animation created using Cinema 4D.