Lost Sinclair, with Simpson/Dunnet, Wick/Canisbay/Stroma connections

130 years ago, James (Jimmy) Sinclair was born in Wick, to Maggie/Margaret Simpson from Stroma and a mystery father James Sinclair, Ploughman, Hillhead, rumoured drowned after the birth. I posted more about this on the genealogy board and someone suggested I also post here in case it jogged any memories. Maggie, the mum, went back to Canisbay, had another daughter Helen McGregor in 1891 then married John Dunnet in 1893 moving to Castletown. The son, Jimmy Sinclair, went to school in Wick, then moved to Edinburgh until his death in 1964 and returned regularly to Wick and Castletown. No one has ever identified the Ploughman father and there is no record of the son ever being with him as he lived with his mum's family the Simpsons in Wick, including a Clyne family when his aunt married a John Clyne. Did James Ploughman drown, did he move away, did he stay? Has anyone heard of this story or know anyone in it? Jimmy Sinclair 1867-1964 was my great grandfather.