Diving the Cape Peninsula and False Bay/Giant's Castle

Maximum depth is reported as about 33 m, probably on the sand to the east of the reef, and the top of the highest pinnacle is about 17 m. Average depth of a dive is likely to be about 24 m.

Visibility is likely to be similar to the other reefs in the Miller's Point area, but may be better due to less surge at depth, but darker, due to greater average depth.

The reef is quite compact, being roughly 70 m from east to west, and 50 m from north to south, with an irregular perimeter and surrounded by fairly flat sand. The group of tall pinnacles is to the west of the reef, and is made up of a tight group of tall outcrops and boulders up to 10 m high, partly separated by narrow, deep gullies, rising from low reef or sand.

Geology:

Pre-Cambrian Granite of the Peninsula pluton, surrounded by mostly fine quartzitic sand and shell fragments.

The site is exposed to swell from the south and south-east, and to wind chop from the north-west, so should be dived in westerly swells, and preferably in moderate winds.

The site will generally be at its best in winter but there are also occasional opportunities at other times of the year.

The top of the reef is heavily encrusted with black mussels, possibly the invasive alien Mediterranean mussel, Mytilus galloprovincialis, but from about 20 m downwards this opens up to more typical reef ecology of this area and depth range, with moderate numbers of sea fans, reef fish, sea anemones and the usual starfish, sea cucumbers, feather stars and brittlestars, including a few basket stars.

The site will generally provide good opportunities for macro photography, but on a really good day, the topography should be good for scenic wide-angle shots. Artificial lighting will usually be necessary.

For your first dive at the site there is plenty to look at around the pinnacles, and on the sand nearby. For subsequent dives it may be worth exploring the unmapped eastern parts of the reef, or the lower profile outliers to the north.

No site-specific hazards have been reported, though the site is in an area of relatively heavy small-boat traffic when fishing is good.

No special skills are needed, though the ability to deploy a DSMB is recommended so that the dive boat can keep track of you during ascent, and so that passing boat traffic can avoid you.

A DSMB and reel is recommended for safety reasons, a good wetsuit or dry suit will keep you warmer longer, and Nitrox will allow a longer bottom time.