Actually, the ship normally experiences a fair bit less than a standard G -- more like a bit between 1/6 and 1/3 gee. Frantisek is a bit of a weakling, dissipated via his hedonistic lifestyle.
When in orbit, the gravity effect has to do with tidal force on a 2/3-mile long body. When under way, it has to do with the way the sector-field is tuned. We try to keep things reasonably consistent with both known physics and the fictional technologies we describe, but when you're doing the pirates-in-space bit sometimes ya gotta fudge a little. Work with us here.