The way it was explained to me by my insurer, negligence is anything that happens on the boat that I didn't do enough to prevent, like someone falling down the stairs. I could have prevented someone from falling down the stairs by installing an elevator. That's what waivers are for. Gross negligence is when I push someone down the stairs. Waivers don't help in that case, so we've taken the gross negligence clause out of our waiver, on advice from our corporate lawyer and insurance company. That's what insurance is for.
I disagree on with your insurer on gross negligence. Knocking someone down the stairs because you are trying to squeeze past them is negligence. Pushing someone down the stairs because you are in a hurry to get down them and the person is in the way may be gross negligence. Pushing them down the stairs so they'll be injured is intentional and probably conscious disregard. Pushing them down as a bad practical joke is a wobbler between gross negligence and intentional.
One court has stated: Under California law, gross negligence is defined as an act or omission that shows a failure to exercise even slight care or that constitutes an extreme departure from the ordinary standard of conduct. Further It requires negligent conduct which is aggravated, reckless or flagrant so as to connote[] such a lack of care as may be presumed to indicate a passive and indifferent attitude towards the consequences of one's acts to the safety and welfare of others.
A few examples from California law:
1. An expert snow skier was warming up for a race and by racing down a ski run. He was in complete control, but was inattentive when he reached the flats at the bottom of the run and as a result crashed into another skier who was stationary on the flats after completing a run. The central question in the ensuing lawsuit was whether the racer's "engaged in reckless conduct totally outside the range of the ordinary activity in the sport." As guidance for the trial court and jury, the Court of Appeal stated: "While racing down an advanced run is part of the thrill of snowboarding, intentionally speeding into a flat area at the base of an advanced run where people have stopped to rest, when one is unfamiliar with the area, without looking where one is going is not an integral and unavoidable part of the sport. [The racer's] conduct is analogous to a freeway driver who exits the freeway without slowing down or looking for other cars that are also exiting."
2. A developmentally disabled 14-year old child who suffered from cerebral palsy, epilepsy, and other disabilities, was enrolled in a summer camp. Camp activities included swimming. The child was a good swimmer. Because of the risk of seizures, a counselor was assigned to watch her while she was in the pool. The counselor watched the child, but was momentarily distracted and turned her attention from the child. When she returned her attention, the child had disappeared and drowned. The court held that it was for a jury to decide if this rose from ordinary negligence to gross negligence.
3. Several young men were horsing around during a party at someone's home. One decided to toss the other into the pool. Unfortunately, the victim of the prank fell short and was seriously injured when he landed on the concrete stairs. The insurer for the family of the young man who did the tossing asserted the claim was not covered because the injury was the result of an accident within the meaning of its policy. The court disagreed. It reasoned that there was no intent to injure, so the injury was an "accident" and the whole incident was not "inherently harmful" as is the case with sexual molestation.