Capable of ballasting to heavy weather ballast without cargo tanks.
No water in cargo tanks—practically no corrosion; increases expected lifetime.
Easy access to frame structures that are mainly in ballast spaces.
Almost complete discharge of cargo.
Easy tank cleaning.
Increased environmental protection.
B. Added protection against cargo outflow in case of low-impact casualty.
Efficient stripping and tank washing; good cargo turnout.
C. Faster cargo unloading (discharging, tank washing, stripping)
D. Psychological shield in low-impact groundings. (However, due to structural rigidity may cause fracture of shell plating.)
Politically acceptable design.
E. Greater cargo outturn.
Fewer tank washing machines.
Greater protection from minor contact damage or oil spill.
F. Easier to load and discharge.
Good protection in low-impact collisions and groundings.
G. Safety in groundings or collisions.
Easy to clean cargo tanks.
Easy to empty cargo tanks.
H. Pollution protection for certain types of casualties.
Better cargo outturn and pumping performance.
Superior tank washing results.
Better access to inspect ballast tank structure.
Meets legal requirements.
I. Safer than single hulls.
Cleaner than single hulls.
J. Regulations will hopefully force scrapping of older ships.
L. Greater SBT capacity.
Reduced risk of pollution in case of grounding or collision.
Reduced risk of pollution.
Better heating performance.
Better stripping ability.
M. Eggcrate structure in way of side shell and bottom structure resistant to fatigue- related failures.
Inspection-friendly structure if intermediate stringers provided in wing ballast tanks.
N. Double hulls eliminate piping leaks as major source of pollution (no cargo pipes in ballast tanks).