Dave's Cave is one of the six wet cave sites that ForestrySA manages in the Green Triangle forests for CDAA divers. The CDAA listing is brief: 'a ladder, harness, pulley and some ropes are required to access this small site', with a helmet and helmet-mounted light also required. It is graded Cave.

That description says a lot about the character of the dive. Dave's is a small site where most of the effort goes into getting in and out – rigging a pulley to lower cylinders, harnessing up, climbing down with a helmet on – before a relatively short dive in a confined overhead space. Published information on the underwater layout, depth and visibility is lacking, and no secondary sources consulted describe it. Divers should expect the general Mount Gambier pattern for small cave sites: limestone passages or chambers, silt on the floor that clouds easily, and a constant 15°C water temperature.

As a ForestrySA site, it is booked through the forestry online portal and closes on Total Fire Ban days. The requirement for a helmet and rope systems makes it more of a caving exercise than a sinkhole swim, and teams usually include someone with vertical-caving skills. For Cave-rated divers building experience across the region's lesser-known sites, Dave's offers variety and solitude; for visitors short on time, the better-documented sites will be more rewarding. Take the extra time to rig properly and to rehearse the lowering sequence before anyone gets wet. Keep the team small and the plan simple.

Book online through the ForestrySA caving portal (forestrysa.com.au/caving – select the cave and date, then enter diver details); ForestrySA recreation staff can help by email (recreation@forestrysa.com.au) or on 08 8391 8800 during office hours. Collect the key as instructed (Mount Gambier Visitor Information Centre for most forestry sites), then drive into the Green Triangle pine plantations on forestry tracks using the booking directions. Park at the site, keep tracks clear for fire vehicles, and carry gear to the entrance.

Forestry sites are closed on declared Total Fire Ban days. Bring a ladder, harness, pulley system, ropes, helmet and helmet-mounted light for the entry.

Underground sites are unaffected by swell or wind; the constraints are the ForestrySA booking, the key, and fire danger – all forestry sites close on Total Fire Ban days (frequent December-March) and fires are prohibited 1 November-30 April. Heavy rain turns forest tracks slippery and can wash debris into entrances. Water is a constant ~15°C, so long cave dives need drysuits.

Snakes are active near entrances in warm weather.

Rig the ladder and pulley, lower gear, descend with helmet and harness, then conduct a short Cave-grade dive on a continuous guideline within thirds.

CDAA grade: Cave (5L215), owner ForestrySA – book via forestrysa.com.au/caving. Ladder, harness, pulley, ropes, helmet and helmet-mounted light required. Continuous guideline; thirds; three lights.

No operator – CDAA Cave-rated members via ForestrySA booking.