Difference between revisions of "Diving the Cape Peninsula and False Bay/A-Frame"
Revision as of 19:42, 12 August 2009
The dive site A-Frame is one of the more popular sites in the Simon's Town area on the False Bay shore of the Cape Peninsula, in the greater metropolitan area of Cape Town in the Western Cape province of South Africa. Information is provided which may assist in planning Recreational and Research Scuba diving at this site, and links to photographs of marine organisms that have been found there.
The site is reasonably easily accessible as a shore dive, and has areas which are suitable for open water training of novice divers as well as reefs with a wide range of interesting invertebrates.
The site is named for a wooden tripod navigation beacon which has now been replaced by a simple post. The beacon is one of the boundary markers for a marine sanctuary.
Oatlands Point is the first point south of the Froggy Pond area. There is a small group of houses on the seaward side of the main road, and more houses up the mountainside. It is easily recognised by the large flattish topped granite boulder just offshore.
This is in a Marine Protected Area and partly in a restricted zone (2009)
Parking on both sides of the main road. Do not park on the short private access road. Go down the steps at the north end of the access road, along the road to the turning bay and the path (muddy and slippery when wet) between the houses which leads down to the shoreline.
There are three basic entry and exit areas: A large fairly flat, rather slippery rock to the north, a region of small boulders to the south, and long rock, just south of the high rocks to the south of slippery rock.
Do not be tempted to use the small beach to the north of slippery rock except in emergency, as the exit is bumpier than it looks from the sea and the path to the road is very steep and slippery. The swim back to slippery rock is much less effort than the climb.
Make your own choice depending on conditions.
The slippery rock is usually quite good for both entry and exit. There is a boulder on top which is useful for steadying oneself while fitting fins, and a fine example of a False Bay Dolerite dyke intrusion in the Cape Granite of the slippery rock itself. This is a site where the typical “Kelp Jump” entry may be used, as there is adequate depth near the rock, and the edge is rather slippery. Alternatively crawl down the depression on the north side of the steadying rock and wait for a wave. The “Butt Slide” entry is sometimes performed, occasionally intentionally, but can be hard on the suit. To get out, make use of the surge. Go with the flow and get up at the top of the surge, so you are not swept back. Some crawling may be required.
South entry is very convenient as there is a nice flattish rock to rest a camera while putting on fins. This entry might be a bit rough in heavier swell. There is quite a long swim through dense kelp to get out of shallows, which is a bit awkward with camera or SMB, but should be OK without.
The long rock access area is at the end of an alleyway between high rocks on both sides, then slightly to the north over a low domed rock with rather slippery weed on top. It is well sheltered from chop by heavy kelp. The disadvantage is that you have to swim out and in through the heavy kelp.
None. Security is no better or worse than most dive sites in the area. Lock your equipment in the luggage compartment.
Fairly sheltered from south westerly swell, Avoid strong south easterly winds and long period large amplitude south westerly swells. The site may be dived during or after westerly winds, and is generally a good winter dive site. It is also good for night dives, but either arrange for a shore party with a beacon or familiarise yourself with the backgound light before leaving the entry point. The north entry is most suitable for night dives as the return involves fewer obstacles than the other exits.
The site is usually at it's best in winter with offshore winds, but there are also occasional opportunities in summer when there has been a period without strong south easters.
Keep a lookout for times when the swell is from the west and/or is of short period (less than 10 seconds)or is very low, for high probability of good conditions.
If a strong south easterly wind comes up during the dive it can make exit tricky due to wind chop. Check the forecast.
The bottom is generally from 5 to 10m deep on the sand.
Pre-Cambrian granite corestone reefs of the Cape Peninsula pluton.
Sand bottom with bedrock reef and big boulders, some breaking the surface. There are a few swim-throughs among the boulder groups north of the big rock. The big rock is pretty sheer on the south face, with a few deep crevices and overhangs. There are several medium sized boulders a little further to the south. The seaward end of the big rock is also quite sheer, with a small cave, and is on a low flattish outcrop. A ridge of medium height extends beyond this outcrop, with another parallel a few metres to the north west of it. These ridges end about 25m east of the big rock, and a large sheer sided boulder rising from the sand bottom at 10m, to 3m below sea level stands a bit beyond. Beyond this is a group of lower steep sided outcrops, about 8m away to the east. There is a relatively high and small one to the south of the group and a much larger but lower one to the north. The gap between them is about 2m wide with a sand bottom. North of these rocks is an area of sand bottom at 10m depth with extensive patches of black mussel. The reef that extends beyond the big rock has a sand patch to the south with some medium and fairly high outcrops. The sand is loose and fairly coarse in this area. To the south of the big rocks there are some large and medium outcrops and boulders, a few of which nearly reach the surface, and an extensive area of scattered small boulders and outcrops with sand bottom between, getting rockier towards the shore.
Slippery rocks and barnacles at entry/exit. Parts of the path from the road ere slippery when wet.
No special skills required. This is a popular site for training and a permanent buoy has been moored just off Slippery rock at the edge of the sand for this purpose. Much of the site is suitable for snorkelling, depending on conditions, and it is also popular as a night dive site.
A reasonable level of fitness helps when carrying equipment around on shore, and the dive requires several hundred metres of swimming, but if you plan well, most of this can be under water.
This is a good photographic site, with a good variety of seaweed, invertebrates and fish.
A light is useful as there are many deep crevices and overhangs to inspect. A compass can be convenient for keeping track of where you are, particularly at night, and for finding your way back at the end of the dive. Knee pads will protect your suit if you have to crawl out.
(general indication of biodiversity: Fish, Invertebrates, algae) The sessile fauna in the swim-throughs and overhangs is very colourful. There are a lot of anemones, sponges and crinoids. Black mussels patches on sand bottom further out may have large groups of Spiny starfish. The outer reefs have large numbers of Common feather stars and some Elegant feather stars. Perlemoen (abalone)seem to be making a recovery, with numbers of small specimens scattered around the reefs. There is a wide variety of habitats with a wide range of inhabitants.
The selection below are just a suggestion for divers unfamiliar with the site. This is a site where there are a large number of distinctive landmarks, and after a while you can get to know your way around quite well.
Views of the site from the shore.
View of A-frame from the road, showing the path (past the No Parking sign).
The North entry at A-Frame, also known as slippery rock. The small boulder in the right foreground is convenient to steady yourself while fitting your fins. The water in front of the rock is deep enough to use the Cape “Kelp Jump Entry” which became popular at this site in the 1980’s. The dive route usually includes a visit to the rocks in the background, and others in that area which do not break the surface. If you have enough air the boulders and reefs around the big rock on the left are interesting and have a good range of species to see, so visit them on the way back. This is also the usual entry for D-Frame which is straight out about 600m from this point.
The long rock entry at A-frame:
The South entry at A-Frame. This area is more sheltered in some conditions, but the North entry is often more convenient as there is less kelp to swim through. In the right background is the Big Rock. In the centre foreground is one of the entry points to the right of the boulders. You can get out of this entry area by the gaps to left and right of the middle rock group. The large grey rocks are granite corestones. The smaller rounded boulders are mostly sandstones from the overlying strata of the Peninsula Formation.