A 63-year-old firefighter and onetime top triathlete remained hospitalized in critical condition Wednesday following a watercraft training accident near Diamond Head.

Firefighter Clifford Rigsbee, a 21-year veteran with the Honolulu Fire Department, was taken to a hospital in critical condition Tuesday after he was pulled from the ocean at about 10:45 a.m. near the surf break known as Suicides near Diamond Head, according to Fire Chief Manuel Neves.

Also injured in the training accident was the operator of the personal watercraft, who was treated at a hospital and released after the accident, Neves said.

Both firefighters are assigned to Engine 7 on Kapahulu Avenue.

They were part of a crew of five training off Diamond Head, where there were “high surf conditions” Tuesday morning, Neves said.

Rigsbee was on the sled being towed when the incident occurred.

Neves said the operator of the watercraft looked back and saw Rigsbee floating in the ocean and immediately went to his aid.

Also assisting the rescue was an off-duty firefighter, Neves said. The Fire Department also scrambled to get other units, including its helicopter and lifeguards with the Ocean Safety agency, participating in the rescue operations.

Neves said the department is trying to determine what caused the accident and whether Rigsbee had a pre-existing medical condition.

Neves said Rigsbee was assigned to the department’s Training Division. As a firefighter 3, Neves said Rigsbee was the second- in-command whenever Engine 7 responded to an emergency.

He is “very gifted and very talented,” Neves said.

Rigsbee is a member of the Ultraman Ohana, has competed in the Ironman Triathlon and won several Tinman Triathlon competitions.

Loved ones and friends shared their love and positive thoughts on Rigsbee’s Facebook page.

Jenni Cooney wrote: “This is the guy you all know and love. Goofy, fun loving, celebrating life !!!!! Keep these images in your mind as you send him your love and aloha. I am letting him know how loved he is and that hundreds of people are pulling for him.”

Brigitte MacNaughton Egbert sent “love and prayers” to his family and said, “Cliff is so heart, spirit, and physically w. He can do this and will heal.”

Several addressed him as “coach,” and said he taught them to successfully compete in triathlons with the right mindset.

“Cliff, you’ve been my inspiration — you have another race to win! Good luck!” Donald Eovino posted.

“We are all thinking and praying for Cliff, a truly wonderful, kind, courageous human being who has supported and helped so many people,” Ruta Summers wrote. “So Cliff, keep fighting. We are fighting alongside you. If anyone can pull through this, you can! God is holding you in his hands.”