The Coast Guard and Steamship Authority were kept busy with response efforts all day Saturday after the ferry Iyanough hit a jetty in the Hyannis Harbor Friday night.

The high-speed ferry operates between Nantucket and Hyannis.

According to reports from the Coast Guard and boat line, about 50 people were rescued from the ferry after the Iyanough struck a jetty and grounded on the rocks at about 9:30 p.m. on Friday. The incident took place on the ferry’s last trip of the day. Some 15 people were treated for injuries following the mishap, the SSA said in an update Saturday.

The Coast Guard responded with its HH-60 helicopter crew from Air Station Cape Cod, and boat crews from stations Woods Hole, Chatham, and Brant Point.

Weather conditions were poor at the time of the incident with rough seas and strong winds.

The Coast Guard is investigating the cause of the grounding.

The Iyanough was freed from the rocks Saturday afternoon and was en route to the boat line maintenance facility in Fairhaven.

Ferry service to the Vineyard has not been affected.