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.
John Burnett, 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, and they have no idea whether they're going to live or die," Burnett told ABC News.
If the yacht reaches Somalia, the four hostages would likely be taken inland, which would make a fast resolution much less likely.
Burnett 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 alive than dead.
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 and Steven Portnoy contributed to this report.