On the 6th. September 1849 the Brig St. John departed Galway bound for Boston. She dropped anchor at Lettermullen, Connemara, to take on additional passengers. The Master was Martin Oliver from Galway. She had a crew of sixteen. Due to incomplete documentation, the total number of passengers remains disputed and unknown. They came from Galway, Connemara, and Co. Clare. She arrived off Cape Cod lighthouse at 5 pm. on the evening of the 6th. October, having crossed the Atlantic in good time under favorable conditions. In the early hours of Sunday, the 7th, off Scituate light, a sudden and unexpected violent storm erupted. St. John changed course a number of times to counteract the shifting wind and maintain her course. The masts had to be cut to maintain stability. The anchors were dropped but failed to hold. St. John was driven, out of control, before the storm. She was wedged firmly between the rocks at Grampus Ledge, Cohasset (42-15-57N. 70-46-48W). where she was pummelled to destruction. The steamer ‘R B Forbes’ from Boston sailed to her rescue but had to abandon the attempt. The Cohasset lifeboat also tried but due to bad communication with Martin Oliver, poor visibility, and confusion with another ship, the Kathleen, the attempt failed. The death toll was estimated to be between one hundred and forty-four and one hundred and sixty-four passengers and crew. (Source: The Northern Maritime Research, Canada) Forty-five bodies were washed ashore in Cohasset. The remainder were never recovered. There were twenty-two survivors.
St. John was a two hundred-ton cargo ship with two masts. Her design was classed as a Brig. The shipyard of construction is unknown. On Thursday, July 30, 1840, The Connaught Journal reported that the Brig John of Youghal went aground off Mutton Island, Galway, the previous Saturday. She was floated and towed to Nimmos Pier where she sank. This may well be St. John that Henry Comerford of Merchants Rd., Galway, and Ballykeale House, Kilfenora, Co. Clare, used to transport the unfortunate emigrants to America on the 6th September 1849. The writer Henry David Thoreau wrote afterward that some of the wreckage of St. John on the beach of Cohasset was “so rotten that I could almost thrust my umbrella through them.”