The Lifeship by Gordon R. Dickson & Harry Harrison. Baen Book 1975
Castaways between the stars...
Trapped in the confines of their fragile lifeship, a tiny band of aliens and humans faces the awesome challenge of survival after the mysterious explosion of a giant spaceship.
Giles Steel, a member of Earth's master race, assumes responsibility for erupting tempers, the dwindling food supply...and the saboteur whose ugly work has already begun!