When 75 years or more have passed since a ship has been wrecked or abandoned, its remains are classified as a ‘historic shipwreck’ under the Historic Shipwrecks Act 1981, and protected from damage or interference, regardless of whether they have been discovered or not.

Some shipwrecks are considered to be so significant, or are at an increased risk of damage, that additional protection is necessary. In these cases, the South Australian Government may declare a protected zone around the shipwreck. Protected zones can be any size and shape up to a maximum of 100 hectares.

A permit is required to enter a protected zone with any type of vessel, or to conduct any type of underwater activity such as scuba diving.

Currently, two historic shipwrecks in South Australia have protected zones around them:

1. Zanoni

The 338-ton composite barque Zanoni capsized in a squall and sank without loss of life in the upper Gulf St Vincent, about 50 km south east of Ardrossan, on 11 February 1867.

Zanoni is one of the most intact shipwrecks of its type in SA, and possibly Australia. It was declared as an historic shipwreck under the Historic Shipwrecks Act 1981 on 12 May 1983, and a 550-metre radius protected zone was declared.

Entry into the protected zone is illegal without a permit. In 1984 a barge was sunk 1 nautical mile south of the Zanoni to act as an alternative place for fishing.

2. South Australian

The barque South Australian, which brought some of SA's earliest settlers in 1836, was servicing the Encounter Bay whaling station. On 8 December 1837, while the vessel was anchored at Rosetta Harbor, a south-easterly gale caused the vessel to part its cables, cross Black Reef and strike the inshore reef close to the current location of the Yilki Store.

Although the wreck site is already protected as an historic shipwreck under the Historic Shipwrecks Act 1981, a 30-metre radius protected zone was declared over the South Australian due to its high significance to the history of SA. Entry into the protected zone is prohibited.