The Nautilus is the historic wreck of the 1770 area. Built in 1880 by J. Walker & Co. of Maryborough as a steam hopper barge, the 260-ton iron vessel (about 135 ft or 41 m) later worked as a coastal steamer. Marinelife.org.au records that she was damaged on the Pioneer River at Mackay in 1928 and patched with cement, and was lost in heavy weather off Bustard Head while under tow from Mackay to Brisbane. The wreck was rediscovered in 1999 during a Royal Australian Navy mine-sweeping exercise.

The hull lies in about 27 m and is described as intact and penetrable – remarkable for an iron vessel that has been underwater for nearly a century. The attraction, though, is the fish. Local divers rate the Nautilus alongside the famous SS Yongala for fish life: marinelife.org.au reports huge numbers and sizes of fish, large grouper, cobia, eagle rays and 'just about every species of pelagic fish'. On a good day the wreck is shrouded in baitfish with trevally and mackerel working the edges.

Visibility averages around 10 m and there is usually a slight current, so this is a dive for Advanced divers comfortable in open water. Penetration of the hull should only be attempted by trained wreck divers with a torch and line, as silt and the age of the structure are real concerns.

Access is the main limitation: the wreck lies off a remote headland, the nearest ramps are small, and there is no regular operator. Boats usually combine it with Outer Rock nearby. For experienced divers with their own vessel or a technical charter from 1770, it is one of the most rewarding and least crowded historic wrecks in Queensland.

The wreck is more than 75 years old and so is protected as historic shipwreck – nothing may be removed.

Boats launch at the Seventeen Seventy boat ramp on Round Hill Creek (at the end of Captain Cook Drive in the town of 1770, about 6 km north of Agnes Water; the town is 2 hours' drive north of Bundaberg via Rosedale or the coast road). The Round Hill Creek bar is shallow and should be crossed on the top half of the tide in a calm sea. From 1770 run north-west around Bustard Head to the wreck – roughly 25-30 km by sea, allow 45-60 minutes.

Alternatively launch at Turkey Beach (a small settlement about 40 minutes' drive north-west of Agnes Water, reached via Round Hill Road and Turkey Beach Road), which is closer to Bustard Head. Drop a shot on the wreck; there is no mooring. The Nautilus is often paired with Outer Rock as a second dive.

These offshore sites lie north of the protection of K'gari and are exposed to the south-east trade winds that blow for much of the year, so they need a calm spell – winds under about 12-15 knots and seas under 1-1.5 m – for a small boat to make the run and anchor safely. North-westerly and westerly winds in winter give the flattest seas and the best visibility (up to 30-40 m on the outer wrecks). The wrecks are tidal: plan to dive at high-water slack, and prefer neap tides, as the current can run hard across open sand on springs.

The Round Hill Creek and Turkey Beach bars are shallow and dangerous on a low tide with swell. Summer brings northerly sea breezes, storms and cyclone risk (November-April).

Descend the shot onto the hull at 20-24 m, tour the exterior into the current first, then drift back along the other side. Wreck-trained divers can enter the intact hull with a torch and line. Keep within no-deco limits, return to the shot and complete a safety stop; if the current picks up, send up an SMB for a live-boat pickup.

Historic shipwreck – protected under the Underwater Cultural Heritage Act 2018; no removal of artefacts. Nitrox recommended.

Dive Spear and Sport @ 1770 (opened December 2022) offers technical wreck diving to 48 m for qualified divers on demand; otherwise private boat or club charter from 1770 or Turkey Beach. No scheduled recreational trips.