A 26-foot sloop sank in the Mission Bay Channel Monday afternoon when a freak wave smashed it against the south jetty, the Mission Bay Harbor Patrol said.
Two people on board were rescued by lifeguards, according to Harbor Patrol Officer Francisco Briseno. They were not injured.
Officers tried to tow the boat out of the channel, but it sank, taking on water through a 3-by-8-foot gash in the bow.
At mid-evening, 10 feet of the boat's mast was visible above the waterline, Briseno said.
The wave that knocked the boat into the jetty was only a four-foot swell, but it was out of sync with the flow in the channel and took the boaters by surprise, he said.