Fuel Oil (Heavy and IMO) - Flash point -safety, you need to know if it will off gas when heated or whilst in storage
Viscosity - combustion- you need this to set your viscosity meter ( non feedback)
You will need as assurance of correct bunker type
Lubrication -Flash Point Contamination ( indicates if you have fule leaking into the oil
Viscosity - Contamination ( fuel Oil, other lube oils), Loss of properties- e.g. hydraulic oils typically have Viscosity Improvers which get chopped up in service meaning you get a general loss of contamination