TORONTO — The billionaire co-founder of the Tim Hortons chain is among the targets of a lawsuit that alleges his son sexually and physically assaulted a woman on his luxury megayacht in Florida, according to her unproven statement of claim.

In a suit filed in Ontario Superior Court, Elizabeth Kelly alleges Steven Joyce attacked her on Oct. 24, 2014, aboard the “Destination Fox Harb’r Too” — owned by his father Ron Joyce — at the Bahia Mar Yachting Centre in Ford Lauderdale.

Kelly, of Toronto, who was in Florida to celebrate her 50th birthday, says she and a friend were aboard the custom-built yacht at the invitation of the younger Joyce.

According to the $5.75-million claim — which the defendants say has no merit — Kelly and Joyce, of Halton Hills, Ont., had spent about two hours in a stateroom when another woman knocked on the door to ask about dinner plans.

“Steven Joyce invited the female guest to come in…and insisted that she join them in bed,” the claim alleges.

When the other woman refused, Joyce grabbed her and tried to force her onto the bed, the claim states. In the ensuing struggle, the guest and Joyce ended up crashing down on Kelly on the floor, “causing her to scream out in pain.”

Kelly says her hand was hurt and she suffered “serious and permanent personal injuries.”

Later that evening, she alleges, she and Joyce were leaving the upper deck hot tub when he attacked her.

“Stephen Joyce, without warning, suddenly and inexplicably, forced the plaintiff face down on a chaise lounge and subjected the plaintiff to a vicious sexual battery,” her claim states.

“The plaintiff screamed that he was hurting her and she begged him to stop.”

According to the court filing, Joyce continued to “violently sexually assault” her.

Kelly claims the humiliating assaults caused rectal tearing and bleeding, painful and unsightly bruises, and inflicted “nervous shock.”

Joyce’s father, Ron Joyce, of Burlington, Ont., is named as a co-defendant because, the suit alleges, he didn’t take steps to ensure her safety aboard the yacht, which was built in 2008, has six cabins and can accommodate 12 guests and as many crew members.

The suit also names MV Ships Agencies, the Cayman Islands yacht builder also named as an owner of the US$18-million, 49-metre vessel.

“The owner and Ronald Joyce directly or indirectly created a situation of danger that they knew or ought to have known would precipitate the type of injuries Steven Joyce inflicted on the plaintiff.”

The attacks caused Kelly pain and suffering that includes damaged sexual and social relationships, guilt, anxiety, flashbacks, weight gain and suicidal thoughts, the suit states.

None of the defendants, who have yet to file a statement of defence, could immediately be reached for comment.

However, Ron Joyce, who was not aboard the yacht during the alleged incidents, told the Toronto Star there was “no truth” to the claim while Steven Joyce told the Toronto Sun the lawsuit would be “vigorously defended.”

Kelly did not pursue a criminal complaint as a “personal choice,” a source familiar with the situation told the The Canadian Press.