Warnings about a “historic” south swell with waves approaching 20 feet and dangerous rip currents predictably did little to keep surfers out of the water Saturday, leaving Honolulu Ocean Safety personnel to deal with the consequences.

Many of the 319 rescues Saturday were surfers, according to Honolulu Emergency Services Department spokesperson Shayne Enright.

“A lot of what we saw today was surfers — broken boards and leashes — so a lot of the rescues that we made were via (watercraft),” Enright said.

Among those needing treatment by Honolulu Emergency Medical Services ambulance crews was a surfer who suffered a laceration to the back of his head at Yokohama Bay on the west shore and a woman in Waikiki who possibly broke her leg in an ocean-related incident.

Enright said nearly 230 rescues were made on the island’s south shore, which is being affected by a large swell that will last through the weekend. A dozen rescues were made on Oahu’s eastern shore, while on the west side, Ocean Safety lifeguards performed 38 rescues.

Ocean Safety also received calls about people who were in hazardous places, in particular the Halona Blowhole by Sandy Beach.

“(It’s) extra dangerous because of the high surf in the area, but that area can always be dangerous because people aren’t supposed to be in that area even when it’s calm,” Enright said.

There was also trouble in windward waters, with Ocean Safety and the Honolulu Fire Department responding to a 911 call just before 11:40 a.m. involving two teenage divers whose 10-foot boat capsized in Kaneohe Bay near Kipapa Island.

HFD’s Air 1 helicopter performed an aerial search and located the boat with the pair of male divers. Ocean Safety lifeguards on watercraft secured the divers and after assessing them for injuries, brought them to HFD’s rescue boat, which carried them — and towed their boat — safely to shore, Enright said.

The National Weather Service said surf was expected to build to 18 to 24 feet Saturday night and issued a high-surf warning for all south-facing shores across Hawaii until 6 a.m. Monday. The same advisory was in effect until 6 a.m. today for the east-facing shores of Hawaii island.

The combination of large surf and high tides could lead to beach flooding and harbor surges, the service warned. Surf along east-facing shores is expected to remain elevated and rough into the early part of the week.

The Weather Service said the “historic south swell” was generated from the South Pacific and is not related to the rapidly weakening Tropical Storm Darby, which was tracking southwest of Hawaii island. Forecasters said Darby would have very little impact on Hawaii’s weather.