Warship and Helicopters Tracking Yacht Hijacked by Somali Pirates Two of the American hostages have been away for three years distributing bibles.

Feb. 21, 2011  -- A U.S. Navy warship on Monday continued to track a yacht holding four Americans that was seized by pirates between the coasts of Yemen and Somalia, authorities reported.

The Americans, sailing the world on a Christian mission to distribute bibles, were ambushed by pirates in dangerous waters nearly 300 miles off the Somali coast. On board the yacht were Jean and Scot Adam from California and Phyllis MacKay and Bob Riggle from Washington state.

John Eggers, a friend of Phyllis Mackay, said on "Good Morning America" today that Phyllis and her husband "were on their own boat, that's why I was surprised about this. What I heard is that they hooked up I guess in India, and they joined the Adams, which is pretty common in the sailing industry I guess. People hook up on boats and take off."

"Phyllis has been sailing for quite a few years. She's been on leave now for about three years. She called one night and said she was going to go on sabbatical, said she'd be back in a year, year and a half, and now it's going on three years," said Eggers. "It was a surprise but she is a very independent, very strong woman. She was at the peak of her career in our industry so it was surprising to me and she was just very respected but she wanted to go on this leave with Bob and away she went."

The last time pirates targeted an American vessel - the Maersk Alabama in 2009 - the heist ended with all but one of the pirates killed by US navy sharp-shooters.

"They think they are Americans, they must be rich and able to pay whatever ransom is demanded. However, I think these pirates have made a grave mistake," said Steve Ganyard, former deputy assistant secretary of state, ABC News consultant. "I think in this case they pushed the United States government just too far, and I think there will be a drama that will play out in the days to come."

The challenge for international warships now is keeping the pirates from making it to the Somali shore where they and their hostages can easily disappear.

Pirates held British couple Paul and Rachel Chandler for 388 days until they were paid a ransom believed to be above $1 million.

Back in California, church-goers are praying for a quick return home for the hostages.

John Burnet, the author of "Dangerous Waters: Modern Piracy and Terror on the High Seas," was once himself beaten and kidnapped by pirates.

"They're right now staring down the barrels of loaded guns, held by children, or held by youths, with whom they cannot communicate, and they're just praying that the ransom is going to get paid, Burnet told ABC News. "They have no idea whether they're going to live or die."

A pirate who said he is in contact with the hijackers on the yacht Quest told The Associated Press that a warship and helicopters have been following the vessel.

U.S. officials confirmed Saturday that the vessel seized Friday by Somali pirates off the coast of Oman has four Americans on board. A U.S. Embassy spokesman on Saturday said officials were assessing options and "possible responses" to the situation.

It is believed that Somali pirates currently have 29 ships in their possession and are holding 660 crewmembers hostage.

Speaking with the AP, one pirate who identified himself as Hassan said a warship with a helicopter on its deck is near the Quest.

A second pirate identifying himself as Bile Hussein, and a Somali official in Puntland who asked not to be named, both said the Quest is between Yemen and Somalia, heading for Puntland, on Somalia's northern tip -- a haven for pirates.

"All relevant U.S. agencies are monitoring the situation, working to develop further information, assess options and possible responses," said Matt Goshko, a spokesman at the U.S. Embassy in Nairobi, Kenya, according to The Associated Press.

The 58-foot S/V Quest is owned by Jean and Scott Adam, who have been sailing the boat around the world for the past seven years. As they approached the notoriously hostile waters off the Horn of Africa, the Adams cut back using their radios and satellite systems so their location couldn't be tracked by pirates, but they were still found.

The Adams are members of the Del Rey Yacht Club in Marina Del Rey, Calif. Contacted by ABC News, a marina manager there said he knew of the situation, but was unwilling to comment or give further details at this time.

The couple details their travels on a website, where an entry from last December listed their expected stops in 2011 as "Galle, Sri Lanka; Cochin, India; Salalah, Oman; Djibouti, Djibouti; The Suez Canal; and Crete. That gets us to April."

That path would have taken them directly into the pirate-infested waters off the coast of Somalia. Pirates there have seized oceangoing vessels for large ransoms; just last week two supertankers carrying oil were seized in waters far off the Somali coast.

If the yacht reaches Somalia, the four hostages would likely be taken inland, which would make a fast resolution much less likely.

Burnet added that though the Adams have several strikes against them, including their Western yacht and their Christian ministry, which is despised by Somali jihadists, the couple are far more valuable to them dead than alive.

Pirate seizures have continued in the waters off East Africa despite the constant patrols of by the world's navies, including ships from the United States.

On Thursday, Abdiwali Abdiqadir Muse was sentenced in New York to 33 years in prison for kidnapping and brutalizing Capt. Richard Phillips, who was held hostage for five days in 2009 when pirates armed with AK-47s scrambled up the stern of Maersk Alabama.

The U.S. Fifth Fleet, based in Bahrain, coordinates an international task force that patrols the waters of East Africa. The European Community also maintains a separate anti-piracy mission in the same waters.

ABC News' Dana Hughes, Steven Portnoy, Kevin Dolak, Luis Martinez and Jeremy Hubbard contributed to this report.