John was born 29 August 1802 in Harrington to Thomas Scarrow, a shipwright, and Ann. Presumably John's mother died during his childhood, as his father Thomas was remarried in 1814 to Mary Dalrymple. From this second marriage, John had three siblings: Joseph, William and Jane.

Details of John's early career as a mariner have so far remained elusive, and will probably never come to light. However, it was fairly typical of this era to sign up as an apprentice around the age of 16, and then work up through the ranks to sailor, mate and then master.

Despite the complete lack of surviving crew-lists from this period, it is possible to ascertain a master's movements by consulting the local paper - in this case the Cumberland Pacquet. Each sailing or arrival from the local ports of Whitehaven, Workington and Harrington are covered in the Shipping Intelligence section. Each entry shows the ship's name, master's name and date of sailing/arrival. By consulting these papers the latter half of John's career as a master is now well documented. A table of John's full voyage list is at the bottom of the page.

The first record of John in the Cumberland Pacquet dates towards the end of 1824. He was master of the brigantine Countryman, whose home port was Harrington. Most of John's voyages were between Harrington or Whitehaven, and Dublin. This would almost certainly be in the coal trade. A round trip from a Cumbrian port to Dublin and back would typically take two to three weeks. Whilst it is certain that coal was exported to Dublin, exactly what cargo, if any, went the other way is harder to establish. The ship would need to carry some ballast at the very least, but how adaptable the Countryman was to carrying cargo other than coal is difficult to determine. Also the harbour rules of the time gave collier ships priority over mixed cargo vessels, and this would probably have discouraged mixed cargos on the return voyage.

John and the Countryman also undertook the occasional voyages to Canada in the years 1828 and 1829. The principle exports from Canada would include timber, with perhaps steel, manufactured goods and cotton going the other way. In 1826, John was the master of the brigs Fortune (once) and Defence (three times), presumably when Countryman was unavailable.

In between the frequent sailings, John married Elizabeth Myers on 13th November 1826 in Harrington. Although shown in the Cumberland Pacquet to have sailed to Cardiff 4 days later on the 17th on the ship Defence, this is probably an error, as there is no equivalent arrival entry. His next sailing was back on Countryman, at the end of December.

Unfortunately John died 17 January 1830 in Harrington of a tedious illness. He was aged only 27. In their short marriage, John and Elizabeth had no children. He had written a will however, and made provision for all his sailing instruments to his brother Joseph who was by then aged 14.

An extract of John's will is shown below:

The table below shows John's voyage record since he became master of the Countryman. The source of all entries is the newspaper Cumberland Pacquet, originals held at the Carlisle Record Office, UK.