The McKees had travelled to Bermuda during the America's Cup racing regatta to watch the event.
The Royal Gazette reported that Mary McKee, 62, died after she was knocked unconscious and drowned after the boat she was in was hit by another in Hamilton Harbour.
Andrew Lake was arrested and charged by local police for driving a boat dangerously but the 27-year-old has denied manslaughter.
He was also charged with causing actual bodily harm to McKee and a third person, catamaran captain Charlie Watson.
Mary Mckee died in a boating accident in Bermuda last year.
The McKees and several others had been dining on shore before returning to their boat around 10.30pm, transported there on smaller boats.
McKee explained to the court they were not wearing lifejackets but the night was still and the water was "like glass".
"When we got into the channel, it was really black and dark on the water. There was no moon that night," he said.
Standing at the front of the boat and peering out for obstacles in the water, McKee did not see the boat that hit them and only remembered a "horrendous" noise.
McKee told the court he turned his head and the other boat hit them, fracturing his skull and cracking his jaw in the impact.
It sent him flying through the air and he lost consciousness in the bilge of the boat.
He was picked up by another boat after he came to, but his wife was nowhere to be seen.
"I told them not to worry about me. I said, 'I have got to find Mary — she's still in the water'.
"They went around looking for her in the water, but it was just so black. They were asking me questions and I kept repeating myself.
