The Red River — Peter Tonkin

Richard Mariner has just ridden out an earthquake powerful enough to destroy the Three Gorges Dam. He knows he should be ordering his ship, the Poseidon, back down the Yangtze at flank speed. But several things are making him hesitate: Architect Chang, the mother of the Poseidon's captain, is missing and may need urgent help; his wife, Robin, puts humanitarianism far above self-preservation; and he has no intention of leaving his new launch, Marilyn, lost overboard during the earthquake, drifting in the river's shipping lanes...