The Centennial is a harbour wreck with a dramatic history and modest remains. Built in Glasgow in 1863 as the SS Albion, she was a 66 m, 668-ton iron passenger and cargo steamer that ended her career on the trans-Tasman run for the Huddart Parker company. On 23 August 1889, outward bound for Wellington with 52 passengers, she collided off Bradleys Head with the collier SS Kanahooka.

She sank in six minutes into Taylors Bay with her masts still above water; everyone aboard was rescued. Because she lay in an anchorage rather than a channel she was never fully removed, and after more than 130 years her hull has settled into a low, mussel-encrusted mound on the sand in 12–15 m on the eastern side of the headland. The wreck is very broken up and does not read as a ship from a distance: sand has built up around it so that it looks like a small hill covered in mussel shell.

Close up, ribs, hull plates, beams and sections of frame emerge from the sand, and a bollard lies inverted on one side; the layout of bow and stern can be worked out with patience. Twenty minutes is enough to see it all, and it is usually dived as a second dive or as a navigation exercise from shore, because the VIZ club has surveyed it with GPS and published a map for shore divers entering from the Taylors Bay foreshore. Fish life is better than the structure deserves: bream, nannygai, yellowtail, small moray eels in the plating, and schools of striped catfish over the sand, with the usual harbour leatherjackets and, in winter, Port Jackson sharks.

Visibility is 3–7 m. The Centennial suits divers who collect harbour history, VIZ-style navigation enthusiasts, and boat owners looking for a sheltered alternative when the Heads are rough; it is a protected historic wreck.

By boat: 15–20 minutes from Rose Bay ramp or Little Manly, into Taylors Bay on the eastern (Chowder Bay) side of Bradleys Head; GPS 33°50.87'S 151°15.00'E (WGS84). Anchor on the mound, which shows as a rise from 15 m to 12 m. By shore: park in Bradleys Head Road or at the Bradleys Head car park (Sydney Harbour National Park, fees apply), walk the Bradleys Head to Chowder Bay track to the Taylors Bay foreshore and enter off the rocks, then navigate out on a compass bearing; the VIZ club has GPS-surveyed the wreck for shore divers.

Exit the same way.

Inside the harbour the swell is negligible; what matters is tide, rain and traffic. Visibility is governed by run-off – after heavy rain the harbour runs brown for several days and the site is not worth diving – and by tide: the last two hours of the flood bring clean ocean water in through the Heads and give the best visibility, while the ebb drags dirty water out. Wind chop from a strong north-easter or southerly makes small-boat work uncomfortable but rarely stops a dive.

Winter westerlies give the clearest water (10–15 m on a good day). Boat and ferry traffic is heavy at all times, extreme on summer weekends and event days; ascend on a line or DSMB and never in open water away from the boat. Taylors Bay is a popular anchorage; on summer weekends it is full of moored boats and dinghies.

Descend to the top of the mound at 12 m and work around its edges at 13–15 m, picking out ribs, hull plates, an inverted bollard and other fittings among the mussels; a full circuit takes 20 minutes. Continue along the Taylors Bay reef edge if visibility allows, and ascend on the anchor line or close to shore.

No regular operator. Dived by private boats, the VIZ dive club (which has mapped it) and occasionally Sydney Dive Charters as a short second dive after the Currajong or Chowder Bay.