York shoal is very seldom dived by recreational divers, because it is fairly far from the launch sites, near a known feeding area for great white sharks, and is virtually unknown to the diving public. Some will dive it because it is there, and to gather more information. Scientific diving may occasionally occur for various reasons, including surveys of the reef life.
- S34°09.367' E018°35.583' 1 York Shoal, 13.7km bearing 077° magnetic from Miller's Point and 24.3km bearing 293° magnetic from Harbour Island, about 2 km SSE of Seal Island
This site is not in a Marine Protected Area. A permit is not required.
The name "York Shoal" is marked on the nautical charts of the area.
Maximum depth is about 28 m at the edge of the adjacent shingle bottom (smallish loose rocks, usually rounded by the action of water), and the top of the reef is about 4 m. Average depth of a dive is likely to be about 18 to 20m m.
Visibility is likely to be whatever is prevalent on the west side of False Bay at the time. The site is far enough offshore to not be much affected by coastal effects, and is in a reasonably sheltered area for swell with a westerly component. On a sunny day the surface water may well have an algal bloom, particularly since the shoal is near to Seal Island, and the water is likelier to be richer in nitrates than average. If there is an algal bloom, the deeper water may be quite a bit clearer than near the surface, but it may be quite dark at depth. There is less kelp and other seaweed at the top of the reef than one might expect, and this suggests that the light levels are consistently low. There is insufficient data to be sure.
The reef is hard sedimentary rock with strike roughly east-west and dip about 10 degrees to the north, consequently the relief is mainly low flattish ridges and gullies, with no known steep or high dropoffs.
Geology: The geology is not known. For some time it was suspected to be peninsula granite, due to the proximity to the obvious granite outcrops of Seal Island, but the reef is clearly durable sedimentary rock, some of which is dark grey and fine grained. It has a similar feel to the reef of Table Bay, which is known to be Pre-Cambrian Tygerberg formation, and the proximity to Seal Island supports this conjecture, as it is below the level of the top of the nearby batholith, therefore likely to be older.
Boat access only: the site is several kilometers offshore.
The shallower part of the reef is dominated by heavy growth of red-bait ascidians, with patches of black mussel, quite probably the invasive Mediterranean mussel. Also moderate numbers of sandy anemones, striped anemones and false plum anemones, and some gorgonian sea fans, which become more common at greater depths. Hottentot seabream and klipfish are fairly plentiful.
Not a particularly scenic dive, and visibility is unpredictable, so macro may be the best bet.
Not enough is known about the site to recommend any routes.
The site is in an area known for the number of Great White sharks, and near a known feeding area for these apex predators.
No special skills recommended. There is a large area above 18m and therefore suitable for entry level divers.
No special equipment required, but it is a large reef and if you surface away from the shotline, a DSMB will be useful to make your position visible while ascending and when you reach the surface.
- 1 Choirboys Reef
- 2 Seal Island
- 3 Drop Zone
- 4 East Shoal
- 5 Moddergat
- 6 Sterretjies Reef
- 7 SAS Fleur
- 8 Steenbras Deep - North Pinnacles
- 9 Steenbras Deep - South Pinnacles
- 10 SATS General Botha
- 11 SAS Bloemfontein
- 12 Whittle Rock
- 13 Bellows Rock
- 14 SS Lusitania
- 15 Rocky Bank