Widening of PANMAX and POST PANMAX Container Vessels

An innovative step to increased cargo intake, improved economy drastically, become much more eco-friendly and stabilising ships value for the future

As a consequence of slow steaming and demands for enhancement of cargo efficiency wide-beam ships have become increasingly popular. The traditional PANMAX container ship with beam dimensions limited by lock sizes to 32.20m and stabilized by huge quantities of ballast water lost the interest in the market as well as deployment.

Not limited to PANMAX vessels, the market potential of performance and capacity increase of POST-PANMAXES is even bigger. Thinking about the excess engine power of the previous generation of vessels ranging from 6,000 – 9,000 TEU, the capacity can be easily enhanced by 40% in loaded container by just a moderate increase of total fuel oil consumption.

Until 2010 the PANMAX size Container Ship with 3,000 TEU to an eventually maximized capacity of 5,000 TEU was the backbone of container sea transport. Today so-called “wide-beams” have become the favourites as wider ships have a greater stability and need lesser amounts of ballast water.

Simultaneously the operational speeds of the vessel have been reduced to save fuel but the low use of available engine power means high SFOC and high wear. Due to the expected steady increase in bunker prices the relationship between speed and cargo intake has drastically shifted in favour for the wider beam ships. In addition, the new Panama Canal locks will be opened in 2016. The market situation for the PANMAX ships is poor and is not visible to improve due to raised bunker prices.

However, by converting the slim vessel to a wide beam the economy will essentially rise in comparison to existing larger container ships in low load operation and will be almost comparable with new ECO designs and low EEDI number.

With Owners seeking to expand their shipping capacity in the most economical way, the widening of bigger ships might become most attractive. Following the basic concept of the PANMAX widening, the driving force is to increase the vessels and fleet capacity in a very short time with a very reasonable price.

Several projects of POST-PANMAX widening have been investigated and designed by TECHNOLOG services GmbH in Hamburg whereby the stability gain is significant and can be proven by more than 40%, depending on the number of container rows added to the cargo spaces. The previous generation of POST-PANMAXES – between 8,000 TEU and 9,000 TEU – usually have an excess engine capacity which matches well with the concept of widening, and the market potential hence can be significant.

The widening of containerships by the above principle and step by step procedure has three major advantages: capacity increase, higher stability, i.e. less ballast water and larger slot capacity at 14t homogenous, and better engine utilization at today’s lower speeds due to large displacement with unchanged engine plant.

This results in a much better EEDI (IMO Energy Efficiency Design Index). Thus, CO2 emissions per ton and mile for the widened ship will get significantly reduced. The result looks even better if the CO2 emissions will be related to pure cargo weight.

Widening by two, three or even four rows could become feasible based on analysis of existing hull structure and cost/benefit aspects. Thus, for each ship class, a respective study becomes necessary to determine limitations and efforts.

The figures show the step by step procedure:

 Example PANMAX:

With the widening concept initiated by Lutz Müller (CTO) REEDEREI NSB, TECHNOLOG services GmbH developed for REEDEREI NSB the entire engineering and achieved all DNV-GL Class and Flag State approvals for the widening of M/V MSC GENEVA, as well as her sister vessels M/V BUXHAI and M/V MSC CAROUGE. These conversion works are done by HRDD, Shanghai. These vessels are increased in capacity from initially 4,860 TEU to now over 6,300 TEU. In the meantime, the ship in operation has proven the results as shown below.


Main Characteristics Original Vessel Widened Vessel Difference
Length over all 275.0 m 283.0 m +8.0 m
Breadth 32.2 m 39.8 m + 3 Cont. Rows
Draught Scantling 13.5 m 13.5 m
Deadweight 65,700 t 81,700 t + 24%
Nominal Capacity 4,892  TEU 6,175  TEU + 26%
 Loaded Capacity 14t/TEU 3,109  TEU 4,901  TEU + 58%
Consumption/ loaded TEU (19kn) 4.6   g/nm 3.7 g/nm – 24%

The pictures are showing the step by step realisation of the two PAMAX vessel of NSB already converted:  


A series of 7,000 TEU container vessels have been delivered in the years 2007-2008. Initially designed and powered for a top speed of 25.5 knots, the operational speed is in the range of 18 knots nowadays. By widening of about 10m or four container rows, the capacity is increased by 41% to about 9,790 TEU.

As an alternative measure to a 10,000 TEU newbuilding project, Owner takes advantage of considerable low investment and short delivery and off-hire terms.


Main Characteristics Original Vessel Widened Vessel Difference
Length over all 305.0 m 319.2 m + one 40’ Bay
Breadth 40.0 m 50.1 m + 4 Cont. Rows
Draught Scantling 14.5 m 14.5 m
Deadweight 85,230 t 108,800 t + 28%
Nominal Capacity 6,921TEU 9,793 TEU + 41%
Loaded Capacity 14t/TEU 5,031  TEU 7,240 TEU + 44%
Consumption/ loaded TEU (18kn) 3.6   g/nm 3.1 g/nm – 17%