Horse and Cart is a small sinkhole on Penola Park Estate at Wye, one of two sites (with Tea Tree) that the Perkins family opens to CDAA divers. The CDAA description is brief: eight metres of ladder required; shallow water with algae, some tree debris, small fish in the water, and snakes in the reeds and underbrush. The site is graded Basic Cave in the CDAA listing.

This is not a site for depth or dramatic visibility. The sunlit shallow water supports algae and weed, and fallen timber lies around the margins and floor. Small native fish dart among the debris. Its value is as a quiet, uncomplicated sinkhole close to the Victorian border that can be combined with Tea Tree on the same property and arranged with a simple phone call or email, rather than the formal booking systems of DEW or ForestrySA sites.

The name hints at local folklore – a horse and cart lost into the hole – but no published source consulted confirms the story. Practical preparation matters more: bring an 8 m ladder (or confirm one is in place), plan how to lower cylinders, wear boots for the reeds, and keep an eye out for snakes in summer. It suits CDAA Basic Cave divers looking for an easy, novel sinkhole to add to a Mount Gambier trip. Because the landowner arranges access personally, turn up at the agreed time, leave gates as found and take all rubbish away; the goodwill of private owners is what keeps small sites like this open to the CDAA.

Contact the landowners (Dale and Heather Perkins, Penola Park Estate – 0438 854 724 or lizzie@penolapark.com.au) at least 24 hours ahead. The site is at 117 ACI Road, Wye, south-east of Mount Gambier towards the Victorian border (about 25-30 minutes' drive). Park where directed on the property, carry gear to the sinkhole and bring 8 m of ladder for the descent to the water.

Watch for snakes in the reeds and underbrush.

Unaffected by swell or tide – the limiting factors are access and surface conditions on private farmland. Summer brings heat, snakes and (at some sites) aggressive bees; Total Fire Ban days can close forestry and some private sites and ban compressors; winter rain turns paddock tracks muddy. Shallow water in sinkholes grows algae in summer, reducing visibility in the top few metres; the water below the thermocline is usually clearer and a constant ~15°C.

Snakes are active around the reeds on warm days.

Descend the 8 m ladder, swim the shallow sinkhole slowly among the algae and tree debris, and avoid stirring the floor; a short, easy exploratory dive.

CDAA grade: Basic Cave (5L129), owners Dale and Heather Perkins. Arrange ≥24 h ahead. Ladder and gear-lowering rope needed.

No overhead.

No operator – CDAA Basic Cave members arrange directly with the landowner.