On the Rocks (Arturo Sandus, #1)

Captain Arturo Sanders was having a bad day. First the routine destruction of some ancient automatic defence batteries became a disaster when his ship’s screens failed and he had no choice to abandon ship.
Then he had to rescue two left behind crew people which meant he missed the main shuttle evacuation leaving him and his two companions in a shuttle on their own at the rear.
Then the shuttle was hit by enemy fire just as they traversed the jump point, of course! This sent the shuttle through something to somewhere but not the safe system the rest of the crew had jumped to!
The damage to the shuttle meant they would need a dockyard or failing that they would have to land on a planet to affect repairs which seemed likely as the system had no electronic signature, so space docks looked unlikely.
The third planet was in fact inhabited, but by primitives armed with swords and spears, probably an old Imperial colony that had been cut off and regressed tech-wise. They should be able to land and repair their shuttle somewhere out of the way except of course the engines decided to fail halfway down!
This led to a close encounter with the side of a mountain, followed by a crash landing into a lake.
And then his day got really bad!