The Llewellyn was built in Liverpool in 1884 as a Queensland Government pilot vessel. She proved unstable in heavy seas and spent much of her career on river duties around Brisbane, but during the 1919 seamen's strike she was pressed into service carrying supplies to isolated north Queensland communities. On the evening of 16 July 1919 she left Rockhampton for Bowen under Captain Holloway with eleven crew and two passengers – nurse Rowena Gordon and shipping accountant W.J.

Bradford – carrying about 30 tons of cargo, coal and lighthouse stores. After passing Cape Capricorn lighthouse the next morning, she was never seen again. Heavy gales were blowing, and her forward-stowed cargo may have made her bow-heavy.

Wreckage washed up on St Bees Island, but the ship itself was not found for 78 years. On 7 December 1997 diver Mark Earney, with David Leffman and Debs McLennan, dived a sonar anomaly off Bailey Islet and found her. Leffman's account describes a 30 m hull sitting intact and upright on the bottom, facing into the current, with a squarish wheelhouse, a broken funnel stump and a mast lying across the starboard deck, all covered in soft corals.

A large grouper occupied the wheelhouse; potato cod, coral trout, batfish schools, wobbegongs carpeting the deck, turtles and even tiger sharks were seen, in 10–20 m visibility. The Queensland Museum quickly took control of the site. The wreck lies in about 35 m on a silty bottom in open water, exposed to strong currents.

A permit is needed to approach within 500 m, the site is policed, there are no buoys, and there are no commercial trips. For permitted, experienced deep divers it is an untouched, poignant wreck – the grave of thirteen people.

Boat only, with a permit. The wreck lies in open water about halfway between St Bees Island and Bailey Islet, roughly 35 km north-east of Mackay. Launch at the Mackay Harbour ramp or Mackay Marina and allow about 1 hour in a fast boat.

A permit is required to approach within 500 m of the site because of its historical significance and loss of life; the site is monitored and has no buoys or markers. There are currently no commercial tours in Mackay to dive this wreck (Mackay Isaac Tourism).

Mackay has the largest tidal range on the Great Barrier Reef coast (springs exceed 6 m), so tidal streams around the Cumberland Islands and in passages such as Egremont Passage are strong and visibility is closely tied to the tide – dive neap tides at slack water. The south-east trades (15–25 knots April–September) make crossings rough; the calmest windows are the build-up months (September–December) and winter lulls. Visibility is typically 5–12 m inshore, often worse after wind or wet-season rain (January–April) from the Pioneer River and local creeks.

Marine stinger season (box jellyfish and Irukandji) runs roughly November to May – wear a full-length stinger suit or wetsuit with hood and gloves, carry vinegar. Cyclone season November–April; tropical lows and cyclones can close sites and damage coral (TC Yasi 2011, TC Debbie 2017). Cyclone Hamish (2009) and Cyclone Debbie (2017) affected reefs in the region.

The Llewellyn is an open-ocean site very exposed to currents, on a silty bottom; it must be dived at slack water on calm days.

Descend a shot placed on sand beside the wreck (not on it), tour the intact hull – wheelhouse, funnel stump and the mast lying on the starboard deck – within no-decompression limits at 30–35 m, and ascend the shot at slack water with a long safety stop.

At 30–35 m, bottom time on air is short; EANx 28–30% or a planned decompression profile recommended. Shot on sand beside the wreck; no anchoring on structure; no penetration. Permit from Queensland/Commonwealth heritage authorities.

No commercial operator – Mackay Isaac Tourism states there are no current tours to dive this wreck. Permitted private/club vessels only.