Difference between revisions of "Diving the Cape Peninsula and False Bay/Steenbras Deep"
Latest revision as of 18:31, 30 November 2010
This site is at the southern end of a long ridge. It is not dived very frequently at it is a long boat trip and visibility is not very predictable.
S34°12.64’ E018°45.50’ First (South) pinnacle.
S34°12.137' to 159' E018°45.558' to 578' Second pinnacle.
About 6km west of Boskloof Point and Steenbras River mouth, and shown on the SA Navy charts but not named.
This site is NOT in a Marine Protected Area (2004). A permit is not required.
The name "Steenbras Deep" is a contraction of Steenbras Deep Reef. This has been the name used by divers and fishermen for this reef for decades at least, and is more likely to refer to the nearby Steenbras River than to any of the fish species known as Steenbras, though this is also a possible derivation.
1st pinnacle is about 17m at the highest point, and 30m maximum depth. 2nd pinnacle is about 18m at top and about 27m at the sand
1st pinnacle: (description needed)
2nd pinnacle: Irregular shaped reef about 40m diameter of apparently sedimentary rock. Some jointing or bedding planes about N-S magnetic. If this is the strike then dip is very steep, nearly vertical. Samples of rock are needed. The pinnacle is irregular in shape, with a large number of cracks, grooves and indentations, mostly not very deep. Sand is coarse and shelly with lots of bryozoan detritus at the edge of the reef at about 27m. The top of the pinnacle is at about 18m
Geology: The geology of the area is not known, but the rock is sedimentary, and the shape of the reef is more consistent with sandstone than shale, as it has a chunky, squared off looking structure, much like the Rooi-Els reefs. Strike is not recorded, but dip may be steep, based on the shape of the ridges and gullies.
The site is exposed to wind and waves from all directions, however it is quite deep, so short period waves will not affect conditions on the bottom greatly. Low short swell, light wind is best. There may be a thermocline, and the visibility may change significantly below the thermocline. 17°C at the surface with 2 to 5m visibility above the thermocline and 11°C with 8 to 10m visibility below the thermocline is possible and conditions at depth are not easily predictable. There is no specific time of year for diving this site, you just have to wait for low swell and light winds.
The site is only accessible by boat. It is approximately 10.5 km from Harbour Island, or 10.1km from Gordon’s Bay harbour.
There is quite a good variety of invertebrate life on the reef. It is similar to, but has a slightly different ambience compared with the reefs on the east shoreline, and is very different to the granite reefs on the west side of the bay.
The site is good for photography. (photographic equipment suggestions)
No particular route recommended. Put down a shotline on top of the reef, descend on this and go down the side of the reef to the sand, then work your way up the pinnacle. There is often a slight current, so do not leave the boat unattended. For preference ascend on the anchor line or a shotline, otherwise a SMB should be used. This is not a good place to be lost.
Strong winds may develop over a short time, however these are usually predictable, so check the weather forcast.
Tha ability to deploy a DSBM is recommended. The site is not suitable for novices as the depth is on their extreme limit and the site is far offshore.
A light can be useful if the visibility at the surface is bad. A reel and DSMB are highly recommended, so the boat can find you if you drift away, Nitrox can greatly extend no-decompression time. A dry suit would be good if diving on Nitrox, as it may be quite cold at the bottom.