HMS Guardian was a 44-gun Roebuck-class fifth-rate two-decker of the Royal Navy, later converted to carry stores. She was completed too late to take part in the American War of Independence, and instead spent several years laid up in ordinary, before finally entering service as a store and convict transport to Australia, under Lieutenant Edward Riou. Riou sailed Guardian, loaded with provisions, animals, convicts and their overseers, to the Cape of Good Hope where he took on more supplies. Nearly two weeks after his departure on the second leg of the journey, an iceberg was sighted and Riou sent boats to collect ice to replenish his water supplies. Before he could complete the re-provisioning, a sudden change in the weather obscured the iceberg, and Guardian collided with it while trying