After a discussion with Silver and Kassy, I am retconning some of the fluff. Ships DO have intertial dampeners, allowing for greater acceleration than a meager 1.5G which takes 10 days to get you out of system.
Of course, if you're boasting a military destroyer drive and pumping 700 Gs, then a dampener failure means you're strawberry jam.
Ships run on fusin drives to clear gravity wells. Outside thosem, they can erect a gravitic sheath which a) protects them from top and bottom, but not from sides and not at all from front and back b) has excellent acceleration. Switching on a gravitic sheath inside a stronger gravity field messes up your drives.
To enter hyperspace, ships reconfigure the sheath into colossal gravitic sails, and make the jump. This a) gives up the protection of the sheath b) can be done only out of system c) takes some time.