The Key Biscayne

The Key Biscayne

The Key Biscayne was a jack up oil rig on voyage under tow by two rig supply vessels Lady Sonia and Atlas Van Diemen from a location off Darwin to Fremantle for stacking in Cockburn Sound pending its future employment.

The loss of the rig was the combination of a series of events during the final day when tow lines parted and gale force winds, rough seas and heavy swells buffeted the rig. All 52 persons aboard ‘Key Biscayne’ were evacuated by helicopter and were taken to nearby Lancelin township with out loss or injury.

The Sinking

The jack-up drilling rig ‘Key Biscayne’ was last seen afloat shortly after 1845 hours WST. Friday 1 September 1983, 10 nautical miles off Ledge Point on the coast of Western Australia. Shortly before that time the tow line to the rig supply vessel ‘Atlas Van Diemen’ parted and the standby vessel ‘Argus Guard’, which had been stationed about 5 cables astern, pulled off to starboard to clear the rig as it was running down with the weather. ‘Key Biscayne’ was clearly seen when about 2 cables off the port beam of the standby vessel both visually and by radar.

However, by the time ‘Argus Guard’ completed its turn, the rig was no longer visible and radar contact had been lost

The lead up to the above, the battle of man against nature, the rescue of the personnel from the rig, the attempts to re-attach tow lines, and then the subsequent loss of the rig is a harrowing tale of man against nature and machine. With nature finally winning, however with no loss of live.

The full account of the sinking of the Key Biscayne can be downloaded here
Some accounts of the rescue are available here and also here

Key Biscayne Dive Site

The Key Biscayne now sits upside down with it’s legs splayed out on a sandy seabed in 42 metres of water, the highest point being at 26 metres. The rig is now home to a variety of marine life, and the size of the rig offers experienced divers an unforgettable dive during good weather.

The site is dived annually by divers from Perth when conditions permit. It is starting to degrade with holes opening up in the body letting in light to what was previously a confined overhead environment. The main hull section is slowly settling and collapsing into the sea bed.

Dive site covered in the news here
Diving WA Shipwrecks reference page here

Model Creation

Dived and modelled 27/04/2025 with scholarship funds from Australasian Institute of Maritime Archeology

The model data was collected by 8 divers in 4 teams; Alex Aberle-Leeming, Andrew Oakeley, Callum Girvan, Craig James, Gareth Glasgow, Grant Pretorius, Martin Bovingdon, Matt Kwan, on a single 1 hour bottom time dive.
The divers were supported by Luke Nelson and Dean Tapper (boat), Emma Taylor, Kate Head, Chas Brown, Huon Fairbairn (diver support).

3D Model

The team has chosen not to release the full model at this time as we plan to dive it again to further improve the model.

However due to the significance of the dive site to the WA Diving Community we have elected to release some still images and animations.

Animation