Challenger's Hope by David Feintuch
An alien attack and an admiral's betrayal leave a wounded Commander Nicholas Seafort stranded aboard a doomed ship of arrogant colonists and hostile street children. His crew is rebelious, his ship short of weapons, fuel and food- easy prey for the alien predators now massing to attack. Only Nick Seafort's will stand between his charges and violent death. But is he merely postponing their end?