By installing an Air Cavity System it is possible to design a single-engine single-propeller ship with a capacity of 11,000 TEU and a speed above 25 knots.

1. Knud E. Hansen A/S
Ultra Large Container Ships
Saving Fuel by Reducing the
Hull Friction Resistance with ACS
A Presentation by
DK Group Na.Nv.
&
Knud E. Hansen A/S

2. Knud E. Hansen A/S
12,670 TEU Container Ship
Present Design
Loa.: 400.0 m
Lpp.: 378.0 m
B: 54.2 m
Depth: 29.0 m
Draft: 14.5 m
Speed: 25.5 kn
Power: 2 x 57 MW

3. Knud E. Hansen A/S
12,670 TEU Container Ship
Present Design

4. Knud E. Hansen A/S
12,670 TEU Container Ship
Present Design
Lightweight 53,000 T
Deadweight (draught 14.5 m) 152,000 T
Displacement (draught 14.5 m) 205,000 T
HFO capacity 17,300 m3
Range – 25.5 kn, 15% sea margin, 85% MCR, 13 m draft 26,500 nm
BW capacity 63,000 m3
Number of Container Positions (TEU):
On hatches: 6,410 TEU
In Holds: 6,260 TEU
Total: 12,670 TEU
Loading Condition 1 (14 T/TEU - no water ballast):
On hatches: 14 T/TEU 3,300 TEU ~ 46,200 T
In holds: 14 T/TEU 6,260 TEU ~ 87,640 T
Total: 9,560 TEU ~ 133,840 T
Loading Condition 2 (no water ballast):
On hatches: 5 T/TEU 4,150 TEU ~ 20,750 T
On hatches: 10 T/TEU 1,540 TEU ~ 15,400 T
On hatches: 14 T/TEU 720 TEU ~ 10,080 T
In holds: 14 T/TEU 6,260 TEU ~ 87,640 T
Total: 12,670 TEU ~ 133,870 T

5. Knud E. Hansen A/S
12,670 TEU Container Ship
Propulsion Alternatives:
• Single-propeller – single engine
• Twin-propellers – twin engines
• Contra rotating propellers

6. Knud E. Hansen A/S
12,670 TEU Container Ship
Propulsion Alternatives:
• Single-propeller – single-engine
Theoretical advantages:
• Low installation costs
Technical problems:
• Very low propulsion efficiency and severe risk of cavitation
• A propeller size of approximately 11.5 m – 12 m with 4 - 6
blades and a weight of 200 t can not be produced today
• Building a 125 MW engine is possible but difficult. (Largest
engines today: 14 cylinders, 98 cm bore, 81 MW)
• The engine will be so long that it might participate in the
longitudinal strength of the hull
• Thrust block and propeller bearing will be huge
• No redundancy
CONCLUSION:
Feasible for a 23 kn vessel, but not for a 25.5 kn vessel!

7. Knud E. Hansen A/S
12,670 TEU Container Ship
Propulsion Alternatives:
• Twin-propellers – twin engines
Advantages:
• Reliability because of well proven components
• Short main engines (21 m)
• Reasonable propeller size
• High propulsion efficiency and thereby low fuel costs
• Full redundancy
• Low maintenance costs & limited number of spare parts
• Better manoeuvrability than single-propeller solution
Disadvantages:
• Relatively high installation costs

8. Knud E. Hansen A/S
12,670 TEU Container Ship
Propulsion Alternatives:
• Contra rotating propellers
• Mechanical solution
• Azipod solution

9. Knud E. Hansen A/S
12,670 TEU Container Ship
Propulsion Alternatives:
• Contra rotating propellers
Advantages:
• Short main engine and reasonable propeller size
• Very high propulsion efficiency (10 % improvement vs. twin
screw depending on relation between main engine and
thruster) => less installed power and low fuel costs
• Propulsion redundancy
• Very good manoeuvrability
• Very high flexibility – propulsion and electrical power
• Reduced size of engine room / higher container capacity
Disadvantages:
• Probably higher installation costs than twin-propeller
solution
• No steering redundancy
• Needs careful considerations to avoid cavitation

10. Knud E. Hansen A/S
12,670 TEU Container Ship
Means of Saving Fuel:
• Increasing the propeller efficiency
• Recovering the waste gas heat
• Reducing the friction resistance of the
hull

11. Knud E. Hansen A/S
12,670 TEU Container Ship
Means of Saving Fuel:
• Increasing the propeller efficiency
• PBCF – (Propeller Boss Cap Fin)
– Fuel saving up to approximately 4 %
• High-efficiency propellers e.g. with Kappel
blades
– Fuel saving up to approximately 4 %

12. Knud E. Hansen A/S
12,670 TEU Container Ship
Means of Saving Fuel:
• Recovering the waste gas heat
– Fuel saving 7 - 12 % depending on
sophistication of heat recovery plant

13. Knud E. Hansen A/S
12,670 TEU Container Ship
Means of Saving Fuel:
• Reducing the hull resistance by air
lubrication – Air Cavity System (ACS)

14. Knud E. Hansen A/S
Flat Bottom with Air Cavity System

15. Knud E. Hansen A/S
12,670 TEU Container Ship with ACS
Modified Design with ACS

16. Knud E. Hansen A/S
12,670 TEU Container Ship with ACS
Modified Design with ACS
Loa.: 400.0 m
Lpp.: 378.0 m
B: 54.2 m
Depth: 30.5 m
Draft: 14.5 m
Speed: 26.0 kn
Power: 2 x 57 MW
ACS area 6700 m2
ACS volume 10,000 m2

17. Knud E. Hansen A/S
12,670 TEU Container Ship with ACS
ACS Air Supply System
• Triple air compressors
• Common air feed pipe
• Redundant distribution system

18. Knud E. Hansen A/S
12,670 / 13,370 TEU Ship with ACS
Widened Ship with ACS
Present Ship:
Breadth: 54.20 m
Capacity: 12.670 TEU
Widened Ship:
Breadth: 56.70 m
Capacity: 12.670 + 700 = 13.370 TEU

19. Knud E. Hansen A/S
12,670 / 13,370 TEU Ship with ACS
Speed and Power
• Fuel saving by ACS ~ 7.6 % ~ 28 t per day
• or speed increase ~ 0.6 knots
• or speed increase ~ 0.3 knots + 700 TEU

20. Knud E. Hansen A/S
12,670 TEU Container Ship with ACS
Conclusion
Installation of an Air Cavity System
gives the choice between:
• Saving approx. 7.6 % in fuel consumption
corresponding to approx. 28 t per day
or
• Increasing the speed by 0.6 kn
or
• Increasing the speed by 0.3 kn +
increasing the capacity by 700 TEU

21. Knud E. Hansen A/S
11,000 TEU Container Ship
Single-engine single-propeller design
Loa.: 385.3 m
Lpp.: 363.3 m
B: 51.7 m
Depth: 29.0 m
Draft: 14.5 m
Speed: 24.5 kn
Power: 81 MW

22. Knud E. Hansen A/S
11,000 TEU Container Ship with ACS
Modified Design with ACS
Loa.: 385.3 m
Lpp.: 363.3 m
B: 51.7 m
Depth: 30.5 m
Draft: 14.5 m
Speed: 25.0 kn
Power: 81 MW
ACS area 5200 m2
ACS volume 7,800 m2

23. Knud E. Hansen A/S
11,000 TEU Container Ship with ACS
Speed and Power
• Max. speed with largest available engine
(81 MW) without ACS system: 24.6 knots
• Max. speed with ACS system: 25.1 knots

24. Knud E. Hansen A/S
11,000 TEU Container Ship with ACS
Conclusion
By installing an Air Cavity System it is
possible to design a single-engine
single-propeller ship with a capacity of
11,000 TEU and a speed above 25 knots.