Then again his (James Riach) labours in preaching the word have seldom, if ever, been surpassed by any poor man who had his own and family's bread to earn. Like the rest of his seafaring brethren, 'he got his bread at the peril of his life'. But when driven by storm or stress of weather to the Caithness coast, if in health, he was sure to be testifying for Christ in the streets, or lanes, or any place provided for the purpose; however humble. Nor did he take any thought whether it was Sabbath or Saturday - just as he was, in heavy sea boots and fisher garb - he stood up and spoke the words of life to listening hundreds. Dunbeath, Helmsdale, Portmahommack, Lossiemouth, all in this manner heard from his lips the Gospel of the grace of God.
"James Turner, or how to reach the masses," by E McChardie, page 205.
James Riach was an outstanding revivalist and beautiful follower of Jesus. There is little known of him except that he worked at a time of revival and he ministered in the power of God, so I am sure there were many salvations here.
I do not know when, it had to be between 1860-71, probably several times.