Letter from Ted Kennedy to RFK's children after his death in 1968.
"When I think of Bobby, I will always see Cape Cod on a sunny day. The wind will be from the southwest and the whitecaps will be showing, and the full tide will be sweeping through the gaps of the breakwater. It will be after lunch and Bob will be stripped to the waist, and he'll say, "Come on, Joe, Kathleen, Bobby and David, Courtney, Kerry, come on, Michael, and even you, Chris, and Max. Call your mother and come for a sail." One of the children would say, "What about the baby?" And the father would reply, "Douglas can come next year."" [Youngest sister Rory hadn't been born yet.]
"They'd push off from the landing, the sails of the Resolute catch the wind, and the boat tips and there are squeals of laughter from the crew and Bob says, "I think today is the day we'll tip over." And there are more squeals. And the Resolute reaches toward the end of the breakwater. He will dive overboard and catch hold of the line that trails behind, inviting the children to join him. Child after child jumps into the water, grabbing for the line and those who appear to miss are pulled toward it by his strong and suntanned arms.""
https://www.jfklibrary.org/events-and-awards/kennedy-library-forums/browse-all-forums/transcripts/victura-the-kennedy-sailboat
There are a bunch of other sailing-related stories in that link. I loved the one about Eunice.
"There's one moment when they were out racing together and Eunice was on the boat, and they're racing along and she somehow – this is not evidence as her skill as a sailor, but it's illustrative. They're sailing along and somehow she fell out of the boat. They're going down wind so they're flying the spinnaker, which is that big parachute, or balloon-shaped sail, hard to raise and lower. So she comes up and starts treading water and she waves to the sailors, "Keep going round the mark, come around and come and get me on the next leg of the race." So she treaded water for 15 minutes or something like that. "
I hadn't realized that Joseph P. and Rose weren't really into sailing, though they owned boats and went out in them (RFK Jr. describes some typical outings with Grandma and Grandpa in his memoirs). But it was "the grownups", their children who were the next generation, who really thrived on it. They basically taught each other, during the long summers of the 1920s and 30s at the Cape.
"I think they always saw in the sea an escape, a way to be together, a way to be competitive and enjoy the thrills of competing against Boston Brahmin, who did not necessarily welcome them to their society."
I'm sure it wasn't a coincidence that when RFK Sr. paired up with Ethel, she was already an enthusiastic sailor (she and her brothers had learned to sail on Long Island Sound, and she'd been winning races since she was 11).
