Captain John Walter Roberts (1792 – 2 October 1845) was a Royal Navy officer who served during the Napoleonic Wars and in the subsequent peace.

He received his first command, HMS Shearwater, in 1820, serving at St Helena as well as off the coast of Africa where he made an aborted attempt to find the missionary Heinrich Schmelen in 1821.

[1] With the Napoleonic Wars ongoing, in December 1804 Roberts followed his uncle into the Royal Navy, becoming a first-class volunteer on board Gore's ship, the 32-gun frigate HMS Medusa.

Roberts received substantive promotion on 6 March the following year, and was sent to join the Mediterranean Fleet as a lieutenant in the 74-gun ship of the line HMS Armada.

Through his period in command of the ship, Shearwater served on the St Helena Station, also making visits to the Cape of Good Hope and Mauritius, during which period the ship was at one point caught in a storm, forcing Roberts to throw all of Shearwater's guns overboard in order to stay afloat.

[6][4] Shearwater arrived at Table Bay, the Cape, on 22 January 1821, from where Roberts was given orders to survey Olifants River, make contact with the Nama people to establish trade, and to search for the missing missionary Heinrich Schmelen.

[7] Shearwater was caught in a sudden squall off the mouth of the river in the night of 6 February and almost capsized before the crew got control of the ship, losing the maintopgallant mast in the process.

[8] Roberts then sent a party of seamen ashore with guides who spoke the local languages, but they quickly ran out of water and had to return on 12 February.

[9] Roberts chose to next send out three separate groups in different directions in order to maximise the chance of meeting locals who could guide them to the missing missionary or initiate trade talks.

Having walked inland about 50 miles (80 km) by 23 February, Roberts could find no settlement or sign of life, and chose to return to Shearwater, arriving back on the following day.

Early in 1823 Thracian was sent, alongside the 26-gun post ship HMS Tyne under the command of Captain John Edward Walcott, on patrol to hunt for pirates in the Old Bahama Channel and off Cuba.

After two months of unsuccessful searching in creeks and inlets, on 29 March they received news that the pirate schooner Zaragozana was sailing off Baracoa.

It was decided that the pirate would have to be attacked by boats of Thracian and Tyne, as she had taken up a formidable defensive position in a shallow part of the harbour, while flying the Spanish flag.

He lost no time in following me with the ships, and had reached, by the assistance of Mr. Bull, acting master of the Tyne...nearly within gun-shot, on our capture being complete.

In April Walcott was taken ill and forced to return to England, and Rowley chose Roberts to replace him in command of Tyne.

Roberts continued on the West Indies Station until the end of the year, when he sailed Tyne back to England, transporting with him $500,000 and a quantity of cochineal on behalf of local merchants.