- The advantages of mounting drive shafts externally are
- Reduced 'blade passing' hull vibration and noise
- Increase propeller effcicency as hull in clearer water
- Allows finer stern hull form increaseing hull efficiency and reducing material requirements
- Some disadvantages are
- Propshaft is more open to damage, erosion and corrosion, for some desgins the extended length of the shaft is shrouded.
- Increase hull drag