Open main menu

offshore dive site at the mouth of False Bay

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.


UnderstandEdit

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.

PositionEdit

  • S34°24.93' E18°35.50' 1 Rocky Bank (approximately)

This site is not in a Marine Protected Area (2004). A permit is not required.

  • 2 45 m Ahmed's Bluff drop: S34°25.392’ E018°35.841’
  • 3 36 m Pablo's Steps drop: S34°25.126’ E018°35.756’
  • 4 32 m drop: S34°24.994’ E018°35.463’
  • 5 30 m drop: S34°24.957’ E018°35.473’
  • 6 25 m drop: S34°24.906’ E018°35.478’
  • 7 22 m drop: S34°24.820’ E018°35.473’

NameEdit

 
Divers over Rocky Bank

The name "Rocky Bank" is recorded on the SA Navy charts of the area. It is also a simple description of the area which is a bank of sandstone, mostly between 25 and 30 m deep.

DepthEdit

The top of the bank is at about 22 m. The chart suggests that the area shallower than 30 m is about 2 square kilometres. Most dives reported have been in the 25 to 30 m depth range. It has been difficult to find shallower areas due to the general flatness of the bottom.

VisibilityEdit

The bank has not been dived extensively, but there are indications that the visibility is usually 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 between 10 and 20 m at the bottom. Algal blooms may reduce visibility near the surface to less than 5 m. Visibility can be good to excellent (over 15m) on days when the inshore dive sites are murky, and even Whittle Rock is mediocre. Possibly the Cape Town dive site with the most consistently good visibility.

TopographyEdit

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 m gullies and ridges.

Divers have found it difficult to find the shallower areas due to the general flatness of the bottom. There is no general uphill trend discernible, so one finds local rises of a metre or two, then it slopes down again. Southern areas may have higher profile than northern areas, but the sample is not big enough to establish a trend.

Geology: Sandstones probably of the Table Mountain series. Strike direction is unknown, Dip direction also not known and fairly flat.

ConditionsEdit

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. A choppy sea will give a long, slow, uncomfortable ride.

Get inEdit

Rocky Bank and other offshore dive sites of False Bay
 
Typical reef life at Rocky Bank

This site is only accessible by boat. It is about 24 km from Miller's Point slipway, 31km from Simon's Town Jetty,or 37 km from Gordon's Bay Old Harbour.

SeeEdit

 
Basket star on sponge
 
Sponges, ascidians and other encrusting invertebrates at Rocky Bank
 
Fan hydroid at Rocky Bank

Marine lifeEdit

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. The reef has more the feel of a South coast reef than a False Bay reef, because the invertebrate assemblages have a different character.

PhotographyEdit

If the visibility 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, oranges, and yellows.

RoutesEdit

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.

Stay safeEdit

HazardsEdit

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.

SkillsEdit

The ability to deploy a DSMB is recommended.

EquipmentEdit

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. A personal locator beacon could be helpful if the conditions deteriorate and the boat has difficulty finding you.

NearbyEdit

Back to Diving the Cape Peninsula and False Bay#Reefs

This dive guide to Rocky Bank is a usable article. It has information on location and equipment as well as some complete entries on what to see. An adventurous person could use this article, but please feel free to improve it by editing the page.