Such downsides notwithstanding, the Facebook group now has over 5,000 members, including current and aspiring cruisers. The group’s map displays dots for nearly 350 families at sea. Parents share tips on swimming with jellyfish, recommend the best childproof cushion covers and discuss best safety approaches. On the first of the month, families post their location and the ages and languages of their kids, which allows them to meet up in anchorages and plan play dates.

Traveling in tandem with other kid boats isn’t difficult, given the prevailing winds and cruising seasons. During hurricane months, boats hunker in hubs for months, allowing people to meet their neighbors at sea.

This year, the pandemic restricted those interactions, confining families to their boats and even bringing some journeys to a halt. Mike Reilly, 63, and Terri O’Reilly-Reilly, 54, and their two boys, 9 and 11, spent the lockdown in St. Martin and considered returning to the United States, until Grenada, a verdant island in the East Caribbean, opened up. This year, this popular kid boat destination during hurricane season also turned into a refuge during the pandemic.

“Good morning, Grenada, and welcome to the kids’ net!,” a chipper voice comes on the VHF radio broadcast twice a week. Kids chime in with introductions, goodbyes and activity announcements. At “Camp Grenada,” as it is unofficially called by cruisers, it’s movie night at the marina on Fridays and trivia on Wednesdays.

The Reilly boys have sleepovers and game nights with kid boat friends and spend time at Hog island off the southern shore, where little ones roam with a feral air while parents kick back at the beach bar. “It’s like any neighborhood — all neighbors are keeping an eye out for kids,” Mr. Reilly said.

After putting their children down to sleep in Seattle, Genny Arredondo, 40, and her husband Adam, 39, watch YouTube channels of kid boat families at sea. This ritual helps her heal. In March, she lost a nonprofit job she loved. Shortly after, her father died from Covid-19 just as they began to reconnect after a period of estrangement.