The Ly-ee-Moon was built in 1859 by the Thames Shipbuilding Company in London as a fast, luxurious paddle steamer for the opium trade, 282 feet long and 27 feet wide. She reached 17 knots on trials, the fastest speed yet achieved by a British-built vessel. She worked in Chinese waters for Jardine, Matheson and Company, was bought by the Japanese Shogunate in 1864 and renamed Taihei Maru, and was later sunk after being rammed in Hong Kong Harbour, refloated, re-engined and converted to a screw steamer. The Australasian Steam Navigation Company bought her around 1877–78; she caught fire during a refit at Pyrmont, was scuttled to put out the fire, raised and repaired, and then ran on the Sydney–Melbourne route.

On the night of 30 May 1886, sailing from Melbourne to Sydney in clear, calm weather, she ran at full speed into the rocks at the base of the recently built Green Cape lighthouse. Of the 86 on board, 71 died; only 15 survived (Wikipedia; NPWS gives 76 victims). It remains one of the worst shipwrecks on the NSW coast, and victims are buried in a small cemetery near the lighthouse.

The wreck broke up quickly and lies in two sections as scattered ironwork. McFadyen describes metal fragments and plating jammed at the base of the bommie wall, two bollards, copper piping and bent pipes at 12–14 m, and further north along the eastern wall at 7–9 m an anchor that appears to be from the Ly-ee-Moon and part of the steam engine's cylinders. Beside them are a diesel engine and a small stainless propeller from a much later fishing boat. More plating, girders, boiler sections and rigging fittings lie on the rock platform above. There is not a lot of structure, but the history and setting make it a memorable dive.

Boat access only and rarely dived. Green Cape is about 28 km by sea south of Eden, a long exposed run from the Quarantine Bay ramp that is only sensible on a settled forecast. Small boats more often launch at Wonboyn Lake, but the lake entrance and bar are shallow and can only be crossed within about two hours either side of a high tide of 1.8 m or more, so a trip needs a morning high tide and no southerly swell.

Arriving below the Green Cape lighthouse, McFadyen anchors between the bombora and the western reef but a little way out, at 37°15'55"S 150°03'01"E (AUS66 datum). Divers swim into the gap beside the bommie to find the first wreckage. Pieces of the wreck are also on the rock platform below the lighthouse, reached by the Green Cape road through Beowa National Park.

Green Cape is fully exposed. McFadyen says you need calm seas, no swell at all from the south and very calm conditions from the north-east at most. The shallows (5 m) are extremely surgy and covered in dense kelp even on good days.

Plan around the Wonboyn bar tide window (about two hours either side of a morning high tide of 1.8 m or more) or a flat, stable forecast for the long run from Eden.

From the anchor, swim into the gap beside the bommie: metal fragments and plating among small boulders, then two bollards, copper piping and bent pipes at 12–14 m. Head north as it shallows, then follow the eastern wall to more wreckage at 7–9 m – an anchor believed to be from the Ly-ee-Moon and part of the engine cylinders, beside a later fishing-boat diesel and stainless prop. Avoid the surgy 5 m kelp zone.

Protected under the Underwater Cultural Heritage Act 2018. Remote diving – carry oxygen, VHF and a full first-aid kit.

No scheduled trips. McFadyen reports Merimbula Divers Lodge will organise Green Cape dives for groups depending on weather and season (outside peak periods); otherwise private boats from Wonboyn or Eden.