Difference between revisions of "Diving the Cape Peninsula and False Bay/Rocky Bank"
Revision as of 20:54, 20 September 2009
The dive site Rocky Bank is an offshore rocky reef in the mouth of False Bay, near Cape Town in the Western Cape province of South Africa.
This site has a different ambience to other Cape Peninsula and False Bay sites, and may have better visibility much of the time. The reef is spectacularly colourful in artificial light.
This site is only accessible by boat. It is about 24km from Miller's Point slipway, or 37km from Gordon's Bay.
S34°24.93 E18°35.50 (approximately)
This site is not in a Marine Protected Area (2009). A permit is not required.
The name "Rocky Bank" is recorded on the SA Navy charts of the area. It is also a simple description of the era which is a bank of sandstone, mostly between 25 and 30m deep.
The top of the bank is at about 22m. The chart suggests that the area shallower than 30m is about 2 square kilometres.
The bank has not been dived extensively, but there are indications that the visbility may be better than average for the False Bay region, as the bottom is rocky, there can be a current, and the water is fairly deep and quite far from the coast, so waves will not easily disturb any sediment, and the current would carry it away rapidly. Visibility has been reported at about 20m.
This is a large area, and probably varies considerably from place to place. Reports indicate that a large area is moderately flat sandstone reef with low dip angle, so there are steps rather than ridges. However there are areas with profile in the order of 2 to 3 metres gullies and ridges.
Geology: Sandstones probably of the Table Mountain series. Strike direction is unknown, Dip direction also not known and fairly flat.
The site is exposed to wind and swell from all directions, so should be dived in calm conditions. This may occur at any time of the year. Use the sea state and weather forecasts for planning.
The rocks are encrusted with a large range of colourful sponges, ascidians, soft corals, noble corals hydroids and coralline algae. Shoals of small fish, and larger yellowtail swim over the reef, and occasionally sharks will be seen.
If the visbility is good, almost any equipment should produce good results. Natural light will be blue or green due to the depth, so a strobe or other artificial light will be needed to bring out the bright reds and yellows.
The site is vast and large areas are not distinguished by any notable features. No routes are known yet, find a place of suitable depth and do a drift dive.
Strong winds may develop over a short time. The site is far out to sea, it may be difficult for the boat to see unmarked divers on the surface.
The ability to deploy a DSMB is recommended.
Take the most powerful light you have to bring out the true colours. The natural light is very blue due to the depth. Each group leader should tow an SMB to allow the boat to keep track of their position. Each diver should carry a DSMB or other brightly coloured signalling device that can increase visible height by at least a metre (yellow is considered most visible at sea). A whistle may also be useful in an emergency.