13th Apostle

城市概覽

This granite reef and pinnacle has been known to exist for many years, as there is a break over it in a large swell, but no details were reported until an exploratory party visited it on 3rd October 2010, to investigate what had shown up on a side-scan sonar image from a reef survey by the Council for Geoscience as a massive mound of rock. What they found is a huge granite corestone tor with a variety of interesting topographical features, on a low profile rocky bottom with sand patches.

Position 1 13th Apostle: S33°59.486' E18°19.922' — (top of pinnacle) This site is in the Table Mountain National Park Marine Protected Area since 2004. A permit is required. This site is within the Karbonkelberg restricted area

Name The name "13th Apostle" is a reference to the position at the end of the mountain range called the Twelve Apostles, south of Table Mountain.

Depth Maximum depth is about 24 m and the top of the pinnacle is about 6 m. Average depth on a dive is likely to be about 15 to 18 m

Visibility Visibility is variable, and can be in excess of 15 m on a good day.

Topography

At 18 m the reef extends about 200 m from north west to south east. The top of the reef is a ridge running roughly true east-west, and approximately 10m deep on the crest, which is broken, but quite long. Towards the east side of the ridge is a peak which is about 6 m deep on top. There are several small sand patches in the immediate vicinity, visible in good conditions from the ridge, and a few larger ones further away to the north east, south and west. The bottom is at roughly 23 m on the sand patches near the main reef. The north side is fairly sheer, dropping almost vertically from near the top to about 20 m, possibly lower in places, and is undercut at the east end by an overhang close to the bottom. At the west end of the reef there is a large swimthrough with a high, narrow entrance at S33°59.490' E18°19.902' at roughly 18 m depth at the top and about 3 or 4 m high and only

如何抵達

Access to the site is only by boat, as it is too far to swim from shore. The site is about 13.3 km from Hout Bay harbour slipway, or 14.4 km from Oceana Power Boat Club slipway

必看景點

Marine life

The top of the reef at about 10 m has a fairly dense forest of split-fan kelp, which is quite usual for this area, however thickets of this kelp are frequent down to 15 to 18 m, which indicate that there is often good lighting at this reef, and that implies frequent good visibility. There is also a moderate amount of other brown seaweeds at this depth range, and rather surprisingly, some filamentous green algae. The deeper, more horizontal surfaces appear to be largely colonised by Cape urchins, with olive and purple soft corals, spiny starfish, encrusting coralline algae and brown ball sponges. The steeper, vertical and overhanging surfaces, as is to be expected, carry a dense encrustation of a wide variety of invertebrates, notable among which are sponges, Noble corals, multicolour sea fans, Red bait and other ascidians, bushy and fan hydroids, and dark sea cucumbers. Knobbly anemones, strawberry anemones, granular sea stars, and a range of bryozoans can also be found. Other animals reported from this site include: Cuttlefish, basket stars, Lots of different nudibranchs including Flabellina capensis , gas flame and silver tipped, and white ones with brown spots, furry sponge crab, kelp klipfish, big shoals of large hottentot seabream, and some massive rock lobster deep inside holes.

Features There are several swim-throughs, overhangs and deep gullies, some are described in the Topography section.

Photography If the visibility is good, wide angle lenses with ambient lighting will provide some spectacular views, otherwise macro equipment with flash will almost always produce good results. The use of flash for intermediate distances should be reserved for external strobes to minimize backscatter. Even on a good day there will be some suspended material.

Suggested Routes At this stage only one route is suggested, not because of lack of things to see, but because very few of the features have been mapped.

Enter at the top of the pinnacle, s