When on 11 February 1788 just beyond the Sydney camp Captain John Shea blasted a kangaroo with his musket, he probably did not care that the well-known portrait of the marsupial famed from Cook's 1770 voyage was inaccurate. He was glad enough to be fit enough to hunt, for death had haunted him since the age of twenty-one when his father was killed at the battle of Bunker Hill. Of his four children, all boys, two do not appear to have survived to adulthood. On the voyage to Botany Bay Shea had nearly died of tuberculosis, but he seemed well enough now. That afternnon Shea sat for the first time on the Criminal Court with Judge Advocate, David Collins and others. He, like Collins, had served in Boston in mid 1775. Re-routed there from New York Shea probably had 'thoughts of loin of veal and lemon sauce' as he neared the Harbor, rather than the 'hard as wood, ... lean as carrion ... and rusty as the devil' fare on offer. He probably did not learn of his father's death until he landed at Boston. Shortly thereafter Captain Shea's effects were sold off, the proceeds going to his wife and her large brood of children. His son undoubtedly bid in the street auction for mementoes of his father, but beyond that grief it is as difficult to trace his life in Boston with certainty apart from noting that he was probably on sea-service. He was possibly part of the marine complement of the men-of-war, 'several schooners and armed ships' policing the port. These naval forces were in addition to those of the Army, the latter comnprising now 6767, excluding two uncounted regiments and the marines, in Boston and on Charlestown Neck. Six thousand of these were effectives. According to its critics, the Royal Navy had been supremely inactive ; ... whale-boats ... have insulted and plundered islands immediately under the protection of our ships ...' These moonlight raids by several hundred men had stolen stock, taken hay and burnt down barns on Long and Moon Islands over several nights, and once during the day. They greatly discommoded the newly arrived Light Cavalry forcing them to send their horses temporarily to Charlestown 'where alone there is any chance of grazing.' By mid to late July fresh meat was so scarce that Lord Percy 'killed a foal , had it roasted and invited a party to dinner.' 'Major Musgrave's fat mare was stolen and sold at the market for beef.' To counter this chronic 'scarcity of meat' 'eight sail of transports and a frigate' went to Fisher's Island to collect livestock. Shea may have been on this expedition..
On 19 and 20 July the rebels in their whaleboats attacked the Nantasket Light-house on Brewster Island at the entrance to Boston Harbor. They carried away '1,000 bushels of barley, all the hay, the lamps', some small cannon and some boats. 'The wooden parts of the light-house' they burnt. In the calm the man-of-war, moored 'but a mile from the light0house, nor the navy longboats could catch the Massachusetts whale-boats, 'remarkable for moving quick.' Cannon fire was blocked by 'a small island lying between them and the ship.' Marines from Collins's battalion were sent to protect the artificers sent to make repairs and suffered casualties and imprisonment at the end of the month.
When not in combat marine officers on sea service had little to do. Too frequently they distracted sailors on watch or disturbed them with rowdy drinking sessions, a problem more pronounced in Boston because of the easy availability of the debilitating Massachusetts rum.Conditions on board Royal Navy ships were an improvement on those suffered by troops ashore. Sailorsand marines were 'coolly and cleanly lodged' below decks and there was 'always a little sail of wind in the water that is not upon the Shore.'
By mid-August transports had arrived from Quebec with yet more salted meat, more flour, oats and entrenching tools. Days later a transport ''with about 2,000 sheep and some oxen', was greeted with 'bells ... set to music to the no small joy and comfort' of the besieged. At month's end some drunken British soldiers celebrated by cutting down the Liberty Tree, Boston's centre of 'political Heat', for winter firewood.
In October John Shea was promoted to first lieutenant. Further sea-service saw him advance to captain-lieutenant by 1779. By 1780 his war was over. He married Susannah Linzee, daughter of an official at the Plymouth Naval Base and sister of Captain John Linzee, whom Shea may have met in Boston. Probably to escape a miserable existence on half-pay, in December, 1786 Shea enlisted for service in the New South Wales penal colony. Captain John Shea, as he was then, may have had the strength to bag several kangaroos and hear court cases but the energy to supervise his Company in the building of a barracks at Sydney Cove was beyond him.It was not 'any part of his duty.' Whatever tuberculatory lassitude convinced him of this, by 2 February, 1789, it had killed him. He 'was buried the next day in Miliatry form very Neat and handsom.' In the unseemly negotiations after Shea's death the then Major Robert Ross's attempt to embarrass the colony's Governor Arthur Phillip and his Judge-Advocate, David Collins, came to nought. Lieutenant George Johnston was promoted to Captain-Lieutenant. Ross's nine year old son gained a lieutenancy, which may have caused Johnston, now twenty-five, to reflect with some piquancy on his earlier North American career.