Michael McFadyen's Scuba Diving - Hump Wall
Shellharbour is located just over 100 kilometres south of the centre of Sydney. This makes it within 90 minutes drive of most people in the metropolitan area, and much close for those of us who live south of the Harbour. There are a number of good shore dives (The Gutter, Bushrangers Bay and the Gravel Loader) here as well as many great boat dives. As close as this location is to Sydney, not many divers travel the short distance to dive Shellharbour except to do shore dives. It is almost unknown for people to go there for a weekend.
Well, the dive Club of which I am a member St George Scuba Club, has over the period since 2000 had a weekend dive trip to Shellharbour each year. These have been very well attended. During these trips, we have explored the area a bit and found some great dive sites. Some of these are, of course, known to the local dive shops (as of early 2006 there are three, way too many for such a location, at least one will fail, there is no way there is enough divers to support all three).
Anyway, when we first started going there (not quite true, we spent a week at Shellharbour diving in January 1994), we were shown a number of dive sites by one of our members. He had originally told me that this site was a pinnacle of sorts. We called it Hump 3. However, I have since sounded around the GPS co-ordinate and this could not be called a pinnacle or hump. What this site has turned out to be is a very large section of reef that is an extension of the end of the Bass Point peninsula.
From Shellharbour Boat Ramp, head out almost due east for about 3.5 kilometres to GPS Reading 34° 35' 14"S 150° 54' 36"E (using AUS66 datum - see my GPS Page for details). Check your depth sounder and you will see that the bottom is 34 metres or so on the east and the top of the reef is about 23 or 24 metres (it gets shallower to the west before dropping to 27 metres and then sloping to 30 metres or more). Anyway, anchor as close as you can to the edge of the reef. In the area where the GPS reading will put you, you will find that you are on a corner where the reef runs south and north-west from where you are located. At this spot the reef slopes to the north-east at about 30° and south of the reading it drops in a shear wall.
Once you are on the bottom, head to the east if you are not on the edge and you will quickly see the wall or slope. Head south and follow the wall. The bottom of the reef is 34 metres. The wall has lots of sponges, sea squirts and other fixed marine life. There are a few tiny gorgonias along this section of wall. The top of the wall is essentially flat, but there are some small holes. The top has kelp in some sections. After 7 minutes or so, turn around and come back to the anchor spot. If you have air, continue past the anchor and you will turn to the north-west. The reef slopes down to your right, with the bottom composed of small boulders. Due to the depth, you will only get about 15 minutes before entering decompression if you stay close to the sand or about 20 minutes if you vary your depth.
This site has lots of colourful fixed marine life but there are not that many fish around. We saw a few Port Jackson sharks, some black reef leatherjackets, seapike, yellowtail and one-spot pullers. There are also lots of nudibranches. Despite the lack of fishlife, it is a really interesting dive.
Of course, due to the depth, this is only a dive for the very experienced.