Fast Container Transfers Involving Winged Boats
There may be scope to adapt Boeing’s concept of a container carrying aircraft that can lower itself to pick up a load of 14 containers, to a wing-in-ground (WIG) winged boat that could carry a substantially greater payload of containers at lower transportation cost. The concept would involve the convergence of several related technologies that includes tandem wing and semi-submersible vessel technologies to produce a potentially workable concept.
While ships that sail at comparatively low speed carry the majority of containers that move internationally, there has been a growing market for faster delivery. The result has been the emergence of long-distance railway container transportation services carrying a small percentage of the container market at higher rates between China and Western Europe. Over a period of several years, companies like UPS and FedEx have developed air freight services carrying small parcels. Researchers at Boeing Aircraft Company have designed a computer model of a self-loading container airplane capable of faster delivery than the railway services.
While the train typically carries 100 containers, Boeing’s concept aircraft can only carry 14 containers. While commercial airports impose maximum wingspan and maximum landing weights, there is possible scope to develop seaplanes and WIG vessels of either greater touch-down weight or greater wingspan of both. If Boeing’s concept container aircraft were offered as a seaplane with twin-hull pontoons, a barge could park between the hulls so the plane could lower itself and take aboard a greater payload of containers than could be loaded at an airport. Alternatively, either the barge or the seaplane could be built with semi-submersible capability.
With its fuselage section parked above the barge of containers, the pontoons of either a seaplane or WIG vessel could be partially flooded to lower the vehicle so as to take the containers on board. Alternatively, the barge could be built with semi-submersible capability and lower itself under the seaplane or WIG vessel that reverses over it or before the barge is pushed forward under these craft. The barge would partially be raised to allow the containers to be secured from above then lowered prior to being reversed away from the seaplane or WIG vessel.
When a seaplane or WIG vessel arrives with a load of containers, a partially submerged barge could be parked under the fuselage of containers then raised to make contact with the containers that would then be transferred to the barge. With containers securely aboard the barge, it would be partially lowered to allow the seaplane or WIG vessel to move forward to be refueled and take aboard a new payload of containers. Given the potentially greater payload carrying capability of tandem wing and/or multi-wing WIG vessel technology, there may be scope for the WIG vessel to actually carry barge and containers.
It is perhaps to Boeing’s credit that the company has also built fast hydrofoil boats used in fast ferry services. There may be scope to combine pontoons used on seaplanes with hydrofoils, to allow a heavy seaplane to accelerate to higher speed and in combination with STOL (short-take-off-and-landing) wing design or rotor-wing design (gyrocopter or helicopter), reach lift-off speed to allow for flight. While Boeing did undertake research on a Type-3 WIG vessel dubbed the “Pelican,” the wing designs developed in Germany by Hanno Fischer and by Gunther Jorg offer high payload carrying capability using much narrower wingspan.
Full-scale versions of the tandem wing design of WIG vessel have been successfully tested and there is scope for future research to develop larger versions capable of carrying far greater payload than large seaplanes. A triple hull WIG vessel could be built with retractable hydrofoils and with the ability to direct powerful streams of fast moving air under multiple wings as the vessel accelerates to lift-off speed. It may be possible to include retractable high-speed water jets in the design to further achieve lift-off speed, along with propellers of equivalent diameter as helicopter rotors to generate the necessary thrust.
Towing and/or Pushing
Tractor planes tow gliders on runways to achieve lift-off speed and tug boats routinely tow much larger vessels. High-speed water jet technology that combines large diameter propellers with comparatively small diameter water jets could offer high sailing speed while avoiding the problem of propeller cavitation. The high mass flow rate of the water stream would provide higher thrust than aeronautical propellers and allow high-speed, twin hull watercraft built with hydrofoils to theoretically tow a heavy-haul seaplane to lift-off speed. Alternatively, high-speed tow craft could use helicopter rotor diameter rotors to tow seaplanes or WIG vessels to their respective lift-off speeds.
The fast rearward moving airstream from the large rotors could increase the lift on the upper surface or seaplane wings and under the wings of a WIG vessel to assist both technologies to become airborne, when the towing cable would disengage and be retracted into the towing craft. A water-jet propelled push vessel with high-speed sailing capability could assist a container carrying WIG vessel that involves many times the weight of a seaplane, to accelerate to its lift-off speed and then travel under its own propulsive power on trans-oceanic voyages of several hours duration to perhaps two days duration.
Boeing's “Pelican” purportedly could carry 1,400-tons. At the time, demand for fast delivery of containers was between non-existent to minimal. During this time period, there may be scope for Boeing to re-examine their “Pelican” plane as a possible container transport seaplane. A twin fuselage seaplane version of the “Pelican” may be possible, with wingspans of 500 to 600 feet and carrying containers in both fuselages. Designing the plane to transfer containers to and from barges could allow the plane to carry 2-levels (double-stacked) of containers.
It may be possible for a seaplane container-carrying version of Boeing’s “Pelican” to carry 24 to 30 containers while a multi-wing, twin fuselage WIG vessel built to 2,000 to 3,000 tons capability could carry over 50 containers. A twin fuselage WIG-vessel would involve four hulls, with the two central hulls connected by wings, carrying the containers. The layout would involve two to three rows of threewings across the beam, with both fuselages designed to exchange containers with barges or possibly carry barges loaded with containers. While the WIG-vessel would operate between ocean coastal locations, the seaplane could operate between different nations’ inland lakes.
Protected Seaplane Runways
Several coastal cities that have beaches have built offshore breakwaters from rocks and boulders, placed parallel to the coastline. The parallel breakwater structures prevent severe waves from reaching the beaches and enhance public safety. Stormy weather that produces large waves would affect seaplane runways, unless those runways were protected from such waves by some form of wave barrier. There may also be scope to install seaplane runways for WIG vessels in narrow ocean inlets, fjords, coastal lagoons, intra-coastal waterways and mouths of rivers where adverse wave conditions remain minimal.
The idea behind Boeing’s concept container carrying airplane that can self-load pre-arranged groups of containers suggest possible ways to simultaneously load and-off-load groups of containers between other types of vehicles, such as between a barge and a seaplane. Boeing’s concept plane offers fast turn-around time at airports that involve arrival, unloading, refueling, loading and departure. The same fast turn-around capability may be possible for seaplanes and autonomous WIG vessels that would spend minimal time at the port terminal and optimal amount of time transporting containers over extended distances.
The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.