The pirates took control of the yacht Quest on Friday in the Arabian Sea off the coast of Somalia.
The Quest belongs to Jean and Scott Adam, two members of the Del Rey Yacht Club in Marina Del Rey. The Newport Beach couple has been sailing around the world since 2004 on their yacht, posting updates on their website. The trip was part adventure, part ministry, as they handed out Bibles along the way.
Two other Americans were captured along with Jean and Scott Adams, though they have not yet been identified.
On Saturday night, parishioners said a prayer for Jean and Scott Adams, who are longtime members of Saint Monica's Church in Santa Monica.
Jean Adams's ex-husband Bill Savage says he spoke with her just days ago about this very danger.
"Their feeling was, they had taken appropriate precautions. But overall, they were fulfilling a dream. And when I asked if there's anything that anybody could do, should something happen, her response was, 'Just pray for us. We are fulfilling our dream,'" he said.
Those prayers were said on Saturday night in Santa Monica and elsewhere.
"That's our hope today, that these great people who are taking this holy word and giving it to so many people across this world, that they will somehow return and find safety and come back home," said Pastor Lloyd Torgerson.
At this time, Somali pirates are holding an estimated 660 people hostage. They have been known to torture their captives and use them as human shields.
Experts said the pirates will not likely hurt the Americans because they won't win any ransom money if they do.
The Associated Press contributed to this report.