Diving the Cape Peninsula and False Bay/Atlantis Reef
The dive site Atlantis Reef or Pillars of Hercules is an offshore rocky reef in the Finlay's Point area of the Castle Rocks Restricted area on the False Bay coast of the Cape Peninsula, near Cape Town in the Western Cape province of South Africa.
Atlantis reef is a section of the granite reef of the Castle Rocks restricted zone, so the marine life has been protected for many years and is flourishing. There is no record that the site has been dived in the past, so it is in pristine condition. The two massive pinnacles marking the site and known as the Pillars of Hercules, were known to exist for some time, as they occasionally show up on the echo sounder of passing boats, but they are a really small target and difficult to find again. However in early September 2011, the dive boat Animal Ocean started investigating the site and reported an exceptionally beautiful area of reef with two impressive pinnacles reaching nearly to the surface but with very small peaks, so they do not break very often, and are in any case to some extent in the lee of the Seal Rock at Partridge Point. Further exploration revealed that the surrounding reef includes some areas of high profile reef near the pinnacles, and further offshore, and extensive low profile and broken reef further inshore.
The first GPS survey of the reef places it on one of the sections identified by the Council for Geoscience side-scan survey of 2011.
This site is in a Marine Protected Area (2004). A permit is required. It is entirely inside the Castle Rocks Restricted Zone, so no fishing of any kind is permitted.
The site is dominated by a pair of massive pinnacles, which rise from a jumbled mass of boulders below 18m to within 5m of the surface. The tops of the pinnacles are quite small and pointed, and are probably in the order of 3m diameter, but they spread out to 15 to 20m with roughly rectangular plan at 12 to 15m depth. There is a ledge to the north at about 18m, and a number of very large boulders in the immediate vicinity. There is sand nearby to the south.
To the east of the pinnacles the reef edge comprises medium to large outcrops of granite corestone, with sand between them in the gaps. The reef tends to get lower to the north and more broken to the north west, where large areas are quite low and made up of small boulders and low outcrops.
Geology: Pre-cambrian granite of the Peninsula pluton.