The Lower North Battery and Marine Life

(Information provided courtesy of Lt Cdr P. Nel in conjunction with Public Relations Office)

Lower North Battery is a functional naval firing range authorized by Government Gazette. The lower North Battery (then called Zoutman Battery) was designed by Thibault in 1793 and is the oldest fortification in South Africa that is still armed!

Here, the Fleet conducts training in the use of various caliber weapons throughout the year excluding the peak whale mating period, which is mid-August to mid-November.

Only white smoke and a loud bang

The coastal road between Muizenberg and Simon's Town provides excellent viewing sites however several members of the public have voiced concern about the impact of firing on the marine life.

The impact of live-firing on marine life

Live firing from Lower north entails a projectile or shell which is released due to the conversion of chemical energy into kinetic energy. The byproducts of this conversion of energy (and the rapid movement of the projectile) are sound and smoke. So, how does this impact on the marine environment?

Sound generated by the weapon as it fires the projectile travels very well through the air, and depending on the caliber of weapon as well as the atmospheric conditions, can be heard several kilometers away. Sound generated by the weapons does not however transfer into the water as sound waves do not cross between the two mediums (air/water) well. Just imagine how difficult it is to hear someone talking to you when you are at the bottom of a swimming pool and they are standing outside. The minimal amount of sound that does penetrate is drowned out by the underwater noise generated by waves breaking on the shore and other marine sources of noise.

The smoke generated from the firing is negligible and disperses quickly with no measurable effect on the environment, marine or otherwise.

Projectiles that hit the water lose their kinetic energy very quickly and these rounds tend to break up within 15 centimetres of the surface. These projectiles mostly consist of copper or steel and do not impact the environment other than providing new areas for marine life to anchor themselves.

During live firing events at Lower North Battery, other measures are also put in place to ensure that marine life is not endangered. No firing is conducted if whales are spotted in the range area or near its outer limits. If any whales are spotted, their movement is monitored and firing will only continue once they have moved clear of the range boundaries. Sentries are used to monitor the range with cameras from high vantage points.

Ceremonial Gun Salutes for visiting ships are also conducted from Lower North Battery, however these “salutes” contain no projectile, only white smoke and a loud bang. As such they have no impact on the marine environment.