The 30 students, ranging in age from 8 to 16, were all wearing life jackets. The only injury was to a volunteer instructor who suffered minor scrapes on his knee and foot.
Belmar Mayor Ken Pringle said the wind knocked over 15 to 20 of the small sailboats being used in a learn-to-sail program run by the Belmar Recreation Department.
"It was a little scary while it was going on, but we determined pretty quickly everyone was accounted for and OK," he said.
Police, fire and rescue groups from around the area responded and took the children back to shore. A dozen lifeguards left a beach about a mile away to help with the water rescues.
The Shark River is a generally shallow waterway that collects tidal sediment washed in from the ocean. Some scientists say it's more like a tidal basin or a bay, particularly the part where the students were boating.
The students were sailing in three groups: one closest to the shore in very shallow water, and two others farther out.