Midshipman's Hope — David Feintuch

THE SEAFORT SAGA
There is no pity in the endless night, no mercy in infinite space. We do not belong there. Not now, not ever--unless one man summons the unbreakable will and unyielding discipline to survive the dark, silent hell he lives to challenge...

A hideous accident kills the senior officers of UNS Hibernia--leaving a terrified young officer to save three hundred colonists and crew aboard a damaged ship, on a seventeen-month gaunt-let to reach the colony of Hope Nation. With no chance of rescue or reinforcement, Nicholas Seafort must overcome despair, exhaustion, guilt; he must conquer malfunctions, mutiny, and an alien horror beyond human understanding.
He must save lives. And he must take them, in the name of duty...