I cannot remember what time they opened - on the first day they didn’t open until 1 pm. They did not make you ride with someone else - solo riders were fine and done a lot.
Last week, I believe it was around 9-10AM on nassau & sea day, 1PM on Castaway day. There were certain times it was pairs only. The explanation that was given to us at the time was that the ride was malfunctioning more often with single riders. Not sure how or when they decide this.
I second what runsky said. From what I heard, they judged the single vs double based on the wind speed but forgot to confirm it with a lifeguard. It was also open decently late. I had first dining and went on around 8pm one night! Can't remember what time they actually shut the water off though...
GET UP TO A $1000 SHIPBOARD CREDIT AND AN EXCLUSIVE GIFT!
If you make your Disney Cruise Line reservation with Dreams Unlimited Travel you’ll receive these incredible shipboard credits to spend on your cruise!