William Cossar

Sow and Pigs Reef is a rocky reef in Sydney Harbour, New South Wales, Australia. The reef is situated on the eastern side of the main shipping channel between Middle Head and South Head. It is 150 metres (490 ft) long and up to 70 metres (230 ft) wide. Originally the reef was exposed and resembled a sow and her litter. Explosives were used to reduce the reef, however, and now the reef is only exposed at a very low tide. A number of ships have been wrecked or damaged after hitting the reef.

Eastern Channel Pile Light, also known as the East Wedding Cake due to its shape, is an active pile lighthouse located at the Sydney Harbour, New South Wales, Australia, off Laings Point in the Vaucluse suburb of Sydney. It marks the eastern end of the Sow and Pigs Reef.

The Sydney Harbour anti-submarine boom net was an anti-torpedo and submarine defence net that was in Sydney Harbour during World War II. It spanned the entire width of the harbour from Laing Point (formerly known as Green Point), Watsons Bay to Georges Head Battery, on the northern side of Sydney Harbour. The boom formed part of the Sydney Harbour defences which also included artillery batteries and patrol boats.

Edward Lombe was a merchantman and passenger three-masted barque built in 1828 by Thomas Brodrick, of Whitby, England.

HMAS Watson is a Royal Australian Navy (RAN) base on Sydney Harbour at South Head, near Watsons Bay in Sydney, Australia. Commissioned in 1945 (after three years operating as HMAS Radar), the base served as the RAN's radar training school. In 1956, torpedo and anti-submarine warfare training were relocated to the base, and by 2011, Watson was the main maritime warfare training base, as well as providing post-entry education for maritime warfare officers, training for combat system and electronic warfare sailors, and command training.

Beehive Casemate is a historical fortification located on the banks of Obelisk Bay, in Sydney Harbour, New South Wales, Australia. It is part of the Sydney Harbour National Park.

The Middle Head Fortifications is a heritage-listed former defence establishment and military fortifications and now public space located at Middle Head Road, Middle Head, Mosman in the Mosman Council local government area of New South Wales, Australia. It is also known as the Middle Head Military Fortifications or The Old Fort. The fortifications consist of the Outer Middle Head Battery located at the end of Old Fort Road, the Inner Middle Head Battery located at the end of Governors Road, and the Obelisk batteries reached by a path from the corner of Middle Head Road and Chowder Bay Road. The fortifications at Middle Head formed part of Sydney Harbour's defences. The property is owned by the Department of Planning and Environment. It was added to the New South Wales State Heritage Register on 2 April 1999.

The Sydney Heads (also simply known as the Heads) are a series of headlands that form the 2 km (1.2 mi) wide entrance to Sydney Harbour in Sydney, New South Wales, Australia. North Head and Quarantine Head are to the north; South Head and Dunbar Head are to the south; and Middle Head, Georges Head, and Chowder Head are to the west and within the harbour. The Heads are contained within the Sydney Harbour National Park. Some features located on the heads are heritage-listed on the Australian National Heritage List; such as the Hornby Lighthouse, located on South Head, Australia's third-oldest lighthouse; Macquarie Lighthouse, Australia's first lighthouse, located 3 kilometres (1.9 mi) to the south on Dunbar Head; and the former Quarantine Station on North Head.

Hornby Lighthouse, also known as South Head Lower Light or South Head Signal Station, is a heritage-listed active lighthouse located on the tip of South Head, New South Wales, Australia, a headland to the north of the suburb Watsons Bay. It marks the southern entrance to Port Jackson, as well as lighting the South Reef, a ledge of submerged rocks. It is the third oldest lighthouse in New South Wales. Designed by Mortimer Lewis and listed on the (now defunct) Register of the National Estate and on the New South Wales State Heritage Register since 2 April 1999, with the following statement of significance: A dominant Sydney landmark which appears to have been in continuous use since the 1840s as a controlling point for shipping entering and leaving Port Jackson. The building complex, designed by the Colonial Architect Mortimer Lewis in the early 1840s, is an architectural important example of an early Victorian public work associated with port activities.

Watsons Bay is a harbourside, eastern suburb of Sydney, in the state of New South Wales, Australia. Watsons Bay is located 11 km north-east of the Sydney central business district, in the local government area of the Municipality of Woollahra. Watsons Bay sits on the end of the South Head peninsula and takes its name from the sheltered bay and anchorage on its western side, in Port Jackson (Sydney Harbour). It provides views across the harbour to the Sydney Harbour Bridge. The Gap is an ocean cliff on the eastern side with views to Manly at North Head and the Pacific Ocean. Vaucluse is the only adjacent suburb, to the south.

Watsons Bay ferry wharf is located on the southern side of Sydney Harbour serving the Sydney suburb of Watsons Bay.

The Georges Head Battery, also called the Georges Head Military Fortifications, is a heritage-listed former military fortification located on the Georges Head on Chowder Bay Road, Georges Heights, New South Wales, Australia.The site consists of the original battery and barracks, designed by Colonial Architect James Barnet, located at the end of Suakin Drive, Georges Heights, two later batteries located adjacent to the corner of Middle Head Road and Best Avenue, Georges Heights, and the Beehive (or Lower) Casemate adjacent to the Armoured (or Upper) Casemate in Chowder Bay Road. The Georges Head Battery is one of three forts in the area that were built for the purpose of defending the outer harbour. The other two forts are located at Middle Head and Bradleys Head, Mosman. The fort became a command post in the 1890s for the coordination of all of Sydney's harbour defences. It was decommissioned in 2002 and part of the land is managed by the Sydney Harbour Federation Trust, with other parts managed by the NSW National Parks & Wildlife Service as part of the Sydney Harbour National Park. The property is owned by Office of Environment & Heritage. The site was added to the New South Wales State Heritage Register on 2 April 1999.