Meet the site
Before the Tasman Bridge opened in 1964, the Derwent was crossed by a floating bridge – a long concrete and steel pontoon structure that opened for shipping. When it was replaced, sections were towed away and scuttled; one lies off Droughty Point near a deep trench, and others rest in the Betsey Island graveyard. The Marine Life Network guide describes this section as about 580 ft (177 m) long, sunk unevenly into the mud, with the deck at about 20 m, 20-28 m at the western end and 22 m at the eastern end. It is covered in jewel anemones and hosts mud-dwelling fish. The guide warns that visibility is low and that entering the enclosed pontoon chambers is extremely dangerous, requiring a guideline and extensive experience; the structure has been used for police low-visibility training. For recreational divers the sensible approach is an exterior-only dive along the deck and sides, with a reel for navigation in the murk. The anemones can be spectacular in a torch beam, splashing yellow and white across the concrete. It is a niche dive for experienced local divers who enjoy low-visibility, structure-based diving and Hobart's engineering history. Because the documentation is old, check locally about its current condition and position before planning a dive. The site suits divers already comfortable with the Betsey Island graveyard wrecks who want a more challenging structure dive close to the eastern shore. Bring a sounder, a strong primary torch and a backup, and plan to spend the whole dive on the outside of the pontoon, where the anemone growth is best anyway.
What you might see
Jewel anemones (yellow and white), mud-dwelling fish, sea squirts, crabs, Northern Pacific seastars
Location
Concrete and steel pontoon section (about 580 ft long) from Hobart's pre-1964 floating bridge, sunk unevenly into the mud near a deep trench off Droughty Point.
Facilities nearby
Lauderdale boat ramp; fills in Hobart.
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
marinelife.org.auRecord updated 26 Sept 2026. Source claims are being reviewed.