The X-Bow Option for Future Container Ships
The X-Bow allows for possible lower level forward placement
of the ship’s control-bridge above and immediately behind the bow of future
container ships. Such ships would carry containers to the rear of and stacked
to higher elevation than the bridge, with telescopic air intakes that extend
upward above the containers, located near the ship stern to supply air to the
engine. The combination could offer greater operational versatility on select
ship routes.
Introduction
Container ships carry most of the world’s trade and despite
the pandemic lockdowns being enforced in many countries and ongoing trade
disputes with China, future trade moving aboard container ships is likely to
increase. The closures of factories in China translates to factories producing
consumer goods at competitive prices being opened in other nearby Asian
nations, with major Asian container transshipment terminals processing greater
numbers of containers within as little as a decade. In Egypt, the Suez Canal
Commission has planned for a future where large container ships will sail along
the canal.
Plans are underway to develop twin navigation channels at
greater navigation depth to transit wider, deeper draft, slightly longer and
slightly higher container ships built to 28,000 to 34,000-TEU capacity.
Installing the ship control bridge above the bow allows for higher stacking of
containers while installing telescopic air intakes at the stern area would
allow for air to flow above the containers and into the air intakes. Upon
approach to a bridge, the telescopic air intakes would briefly retract. The
dynamics of the X-bow when sailing through waves enhances prospects for forward
located control bridges on future container ships.
Port Bridges
Ships sail below bridges on approach to many ports
internationally. While some bridges can be rebuilt to greater height as was the
case with the Bayonne Bridge on approach to the Port of New Orleans, bridge
rebuilding is sometimes not a viable option for mainly cost reasons. The combination
of redesigning or reconfiguring a ship and modifying its route operations and
schedule offers a possible solution at several ports internationally. The X-bow
allows for a low-elevation bridge located above and slightly behind the bow,
with containers stacked to well above the height of the bridge.
A ship built to such configuration could sail through severe
wave conditions across the North Atlantic to a transshipment terminal such as
Quebec City or Halifax, where the upper levels of containers would be removed
for transshipment. The ship would rise in the water to shallower sailing draft
and telescopic air intakes retracted to allow the vessel to sail under the
Bayonne Bridge into Port of Newark, under the Arthur Ravenel Bridge at Port of
Charleston, under the Dames Point Bridge at Port of Jacksonville (JaxPort) and
under bridges located between Ports of Montreal and Quebec City.
Ship stresses
Traditional ship bows built with the conventional bow
configuration tend to pitch when sailing into waves. Comparison sailing in
identical severe wave conditions involving a ship built with a conventional bow
and the other with the X-bow revealed that the X-bow responds with less
slamming while the deflector built high above the bow redirects water spray
away from a forward bridge. A vessel built with the combination of X-stern and
X-bow offers reduced pitching when sailing at near steady cruising speed through
severe wave conditions, in turn potentially reducing wave induced structural
stresses along the vessel hull.
Stress induced by vessel pitching motions when sailing
through severe wave conditions is one of the factors that restricts ship
length. Depending on the amount by which the combination of X-bow and X-stern
reduces pitching induced structural stresses, there may be scope to slightly
extend vessel length and slightly increase the number of containers that it
could carry. Further research would be required to determine possible
lengthening of future container ships built with the combination of X-bow and
X-tern, compared to vessels built with conventional bow and stern.
Montreal Configuration
The maximum size of ship allowed to sail to Port of Montreal
would measure 44-m beam by 294-m length. By comparison, the older generation
Panamax ships that sailed to Montreal were built to 32-m beam. A container ship
of 44-m beam by 294-m length and 10-m draft at part load may be built with
combination X-bow and low level forward bridge, with upward extending
telescopic air intakes at the stern area. When sailing on the ocean, it would
sail at greater draft with containers stacked higher than the bridge, to be
partially offloaded at Quebec City container terminal.
After being partially unloaded, sailing draft would decrease
to 10-m with top level of bridge at same height as earlier generation Panamax
ships. Air intakes would be retracted so as to allow vessel to sail to
Montreal, carrying 17-container widths across its hull compared to 12-container
widths of the earlier ship. A ship of such configuration could carry an
additional 40 percent more containers to Port of Montreal compared to earlier
Panamax ships.
Suez Configuration
The future navigation dimensions along Suez Canal parallel
channels would likely allow for 1-TEU additional sailing draft, up to 3-TEU
additional widths, 2-TEU additional height above water with forward bridge and
4-TEU additional length. The air draft restriction imposed by the bridge across
the Suez Canal enhances future prospects for future mega-size container ships
built with a low-level forward bridge, enhancing prospects to consider X-bow.
The need to maximize container carrying capacity aboard future container ships
enhances prospects to research whether combining X-bow with X-stern would
sufficiently reduce pitch motion induced structural stresses to allow for ship
lengthening.
Future trade between Asia and North America is likely to
recover and increase, with larger container ships sailing via the Suez Canal
and Western Mediterranean transshipments ports to North American east coast
ports. The future operational success of container transfer technology at
Halifax transshipment extended terminal would be essential for supersize container
ships built with low-level forward control bridge to partially offload
containers prior to sailing to Port of Newark. Interline ships would then carry
the containers from Halifax to Boston, Portland, also Philadelphia and
Baltimore via Delaware Bay along with ports located along the St. Lawrence
Seaway.
Short Sea Ship
Shipbuilder Ulstein of Norway has undertaken research into
developing a short-sea X-bow container ship of under 10,000-TEU capacity.
However, they have not yet undertaken any research into larger X-bow container
ships. The forward placement of the bridge of the short-sea X-bow concept
container ship allows for partial offloading of containers from the upper
levels at one port, to allow the partially loaded vessel to sail through shallower
water and under bridges to a second port, as would be the situation along the
Lower St. Lawrence River between Montreal and Quebec City.
The short-sea X-bow container ship with its low-level
forward bridge provides the basis by which to develop a future version of 7,000
to 9,000-TEU capable of sailing the trans-North Atlantic service between
European transshipment terminals and container terminals located along the
Lower St. Lawrence River. Successful development of a trans-North Atlantic
version of the short-sea X-bow container ship would subsequently provide the
basis by which to develop larger versions of the ship.
Conclusions
The premium route for an X-bow container ship with forward
control bridge carrying under 10,000-TEU would be the future Europe – Montreal
service and involve partial ship offloading at Port of Laurentia. Future
supersize container ships built with forward bridge roof built below the top
level of containers would sail along a future twin-channel, deeper-draft Suez
Canal while carrying 28,000 to 34,000-TEU. The layout with forward low-level
bridge makes the X-bow an option for future container ships that will sail via
an enlarged Suez Canal. Future research would determine the suitability for the
X-bow to supersize container ships.