© Ian Robertson, 2009
On reading this, please remember that these were the early days of recreational diving and practices have changed significantly since. Also, entry-level diver training was much more comprehensive then than it is now.

In May 1961, our club was diving at the Sleeping Pool at Sinoia (Chirorodziva – the subject of another story).  Robin Ransome, on holiday from the mines in Zambia (then Northern Rhodesia), was passing through and joined us for a dive.  Robin had a substantial air compressor built into the back of his car.  We had a very pleasant dive in 30 m visibility to 35 m and looked at a number of side caves in the pool.  He was most impressed and said he knew of a number of flooded caves and sink holes in Zambia, near Ndola, and invited me for some diving.  This area of Zambia is renowned for Proterozoic limestones. 

A Reavell air compressor - the compressor is ex-Navy and was used to fill torpedoes - very popular in its time.
Help was at hand to carry the gear to Lake Kashiba - Africa-style.

An opportunity came in August, during my University vacation. I took a bus up to Kitwe in the Zambian Copperbelt, close to the Congolese border, where Robin worked at the cobalt refinery.  The next day we set off in Robin's VW Truck, loaded with camping and diving gear.  The first dive was at Lake Kashiba (meaning ‘small lake’), southwest of Ndola.  It was a bit of a hike from where the track ended but help could be hired to get the heavy tanks along a winding bush path.  At last there it was, a rectangular sinkhole about 4 hectares in size, filled to within 10 m of the surface with clear, slightly greenish water and surrounded by Mushitu forest.  The sides dropped shear to the water, but there was one spot where we could scramble down to a small rocky landing and kit up.  Africa is ever the land of myth and legend.  Kashiba was said to have a resident monster “Ichitapa” or “Isoka Ikulu”.  When a man stands at the waters edge with his shadow on the water, the monster comes up from the depths and catches his shadow, paralysing the man who falls into the water. 

Robin checks our kit accumulation at the dive site at Lake Kashiba.
Robin with fans at Lake Kashiba after the dive.

Never mind the monster; in we went.  Visibility was about 10 m and the temperature 25ºC.  At the entry point, the limestone wall underhung slightly.  We dived down a vertical wall.  At 15 m, there was an overhang that cut in and under at an angle of 30º and was stepped with short vertical drops and, in the roo,f a massive fault plane that I steered away from in case of drainage.  Six minutes later, the light had diminished somewhat and Robin was a silhouette beside me, our torches struggling to penetrate the dark water under the overhang.  No sign of a bottom – only the dark roof above us, and greenish grey water below.  I was glad of the short buddy line between us.  At 62 m we stopped, turned around and began the ascent towards the deep green light penetrating from the surface.  Robin was clearly a little narked and apprehensive – so was I.  The ascent went smoothly with the light progressively increasing until we reached the decompression stop, where we waited for 20 minutes before surfacing.

Robin had brought a large reel of line.  While we relaxed in the sun, he tied a lead weight onto the end and used it as a sounding line.  Over 150 m of line went over the side and down, without any sign of a bottom.  Definitely a deep sinkhole!  Lake Kashiba is still a diving challenge.

The slot-like lake Nampamba
Hans and Robin prepare to dive in Nampambas crystal clear water.

That evening we met up with two other divers, Hans Muller, and his girlfriend, Pauline Phillips, and made camp.  The next morning we headed along dusty tracks to Lake Nampamba, a narrow, slot-like sinkhole about 100 m long and 24 m deep, filled with blue, crystal-clear water, redolent with a luxuriant growth of water weed near the edges.  This was a very different site. Visibility was 30 m and the floor was of tumbled blocks.  This was a ‘look see’ dive but, during the dive, we found a cavern amongst the limestone blocks at the bottom that beckoned and I decided to explore it properly on the next dive after a suitable surface interval for lunch and snorkeling. 

Pauline, Robin and Hans relaxing at the slot-like Lake Nampamba.
A subsidiary sinkhole at Lake Ishiku with a high water table.

This time Hans stayed at the entrance and belayed me in on a line.  Apart from my torch, it was quite dark inside and about 15 m across, the roof was at about 25 m.  On the bottom of the cavern were tumbled blocks of limestone at 38 m with a few small, rather tight cavities amongst them.  I explored these briefly but found them hazardous and was glad of the line to Hans.  This was to be a short dive so I returned and found a second exit to the outside, swam round behind Hans and tapped him on the shoulder, startling him.  I think he might have forgiven me by now. 

We also had a quick look at another sinkhole, Lake Ishiku, near Ndola, but our tanks were empty so we could not dive.  Ishiku also has its stories that tell of wrong-doers, weighted with stones, being cast into the lake.  It was time to start the long trip (800 km) back south and home to Salisbury (now Harare).  A long way for three dives, but I was keen then.  During the trip back, I had the opportunity to reflect on what I’d learned.

  • Using a sounding line to measure the depth of an unknown site seemed a good idea before the dive and not afterwards.
  • I was used to nitrogen narcosis in the warm, crystal-clear waters of the Silent Pool at Sinoia but, in the reduced visibility of a strange, dark, unknown cavern, it can take on a very different and more sinister guise.
  • The Zambian sinkholes had a much higher water table, only ten metres or less below ground (Sinoia is 45 m below ground).
  • Lake Kashiba clearly displayed its dangers – primarily depth – but the idyllic Lake Nampamba contained dangers for the unwary too – dark cramped caverns in which you can easily get trapped. These were early days for cave diving.

Since writing this, the internet has enabled me to find and contact Neiles Billanay, who also dived these sites in the early days, and we have compared notes.  Neiles dived Kashiba in the mid 70’s with the Zambian branch of the BS-AC, achieving spectacular depths of up to 72 m.  He explored the connection between the subsidiary lake and the main lake at Ishiku (the roof of this is at a depth of 30 m) and also visited the cavern in the floor of Nampamba (he calls it Mpambu which is probably more accurate).  He then went on to become a commercial saturation diver in the North Sea.  That we did this with learning but without incident might say something about the thorough and enabling British Sub-Aqua Club training of those early days.