Sep 052011


Dean and Anna in Iddlebiddy

About the site

Iddlebiddy Cave is an Advanced Cave rated site located near Mt Gambier, South Australia. Initially discovered in the 1970s by locals Peter Blackmore and Phillip Earl, they were reluctant to report it to the newly formed Cave Diver’s Association of Australia (CDAA) because their lack of formal training under the new system would see them lose their right to dive here.

The site was named Iddlebiddy as it follows a straight tunnel formation for a few hundred metres, and is reminiscent of the massive railway tunnel type cave formations found on the Nullarbor Plain such as Cocklebiddy Cave. While Advanced Cave sites are usually rated for their narrow single-file restrictions, Iddlebiddy is rated to protect the delicate feature of the cave seen in the photo above – the clay blocks.

In addition, access to the water level requires an A-frame and ropes to lower gear down onto a steep rocky slope. Improvements by Forestry SA in recent times have seen a platform and solid ladder on this slope, greatly reducing the prospects of divers falling while gearing up in the cramped entrance room. With a locked lid on the entrance to reduce access by non-qualified people, the small airspace above the water can become high in carbon dioxide, and it’s best to reduce the amount of time spent here when preparing for a dive.

Once into the water, the permanent line runs through a number of distinct sections of tunnel through to a terminal room. There are also a few smaller side passages that can be explored, with some new cave recently discovered here.

About the dive

With it being summer in Australia and the ocean water temperatures in Melbourne hovering around 19 degrees Celsius, the first thing I noticed was the stock standard 14 degree water. Protected from the sunshine (and early morning winter frosts) by metres of rock, the ground water in Mt Gambier stays at roughly the same temperature year round. The caves are lovely and toasty in winter when the ocean is 10 degrees but a bit challenging in mid-summer, especially on the hands and face.

This dive was a photo dive with multiple models and multiple strobes, immediately increasing the difficulty factor. Having an underwater photographer as a model makes life much easier, as Dean has a very good understanding of which direction to point the light in. Anna’s professional underwater modelling skills means the light Dean is holding is hitting her square on and revealing the detail in her black technical dive gear.

My main aim was to get some good perspective on the blocks, while using the off camera light to add depth to the tunnel. With certain areas of the main tunnel having seen more traffic than other areas, some blocks have been left in a less than photogenic state.

About the photo

The main challenge I discovered on this dive was the relatively flat nature of the blocks. This led to difficulty in lighting them from the camera in a way that both revealed the details of the layers of colours and provided shadows. The 14mm lens meant I needed to be less than a foot away, while practising perfect buoyancy control to avoid further damage to the feature I was trying to capture.

I like the top shot because it gives an idea of the extent of these formations, while showing some of the colour variations in the cave. The close up second shot lets you see the distinct layers that have settled out and cracked apart. Close shots of underwater rock tend not to thrill, but these distinctive features make this a beautiful dive. With some care from the local cave divers, hopefully the clay blocks will remain intact for years to come.

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