Prospects to Carry River Barges Across the Ocean
Barges that can be coupled lengthwise and widthwise offer an efficient and versatile means of transportation along inland waterways. Tugs can push and navigate extensive barge tows along such waterways. The ‘restricted’ hull design of river barges presents several challenges when considering sailing across choppy water such as a large lake or small sea. While barge tows may sail along the Danube and Volga Rivers, sailing conditions on the Black Sea discourages barge tow operation between the confluence of those rivers and that sea. There may be application for technology that can transport barge tows across the Black Sea.
One option would be to build the barges with ‘unrestricted’ hulls that may sail across the Black Sea while coupled lengthwise and widthwise. Another option would be to develop a technology that could protect coupled barges built with ‘restricted’ hulls, from the choppy waters of the Black Sea. This option would suggest some form of barrier that could deflect waves around the barge tows, as if the barge tows were in a swimming pool on a larger vessel. A shipbuilder in the Netherlands does offer a semi-submersible vessel called a mobile dock capable of carrying a ship.
The ocean wave energy sector has built floating pools where the water surface that is above the elevation of the surrounding ocean. Waves flow over the pontoons that support the weight of and enclose the floating pool. Boats built with twin-hull catamaran-pontoon technology include inflatable craft where pontoons extend forward and converge to connect at the bow. Pairs of pontoons that converge at the bow would carry submerged wave deflectors that resemble hulls that include tiny motion driven water inlets and outlets.
Pontoon Barge Carrier:
The purpose of a pontoon barge carrier would be to transport coupled barges built with ‘restricted’ hulls on calm floating pools, while the carrier sails across choppy water of lakes and small seas between the mouths of navigable rivers. While pontoons would form the sides of the carrier vessel, one version may feature a pontoon stern while another version may feature converging pontoons at the bow. While ‘aboard’ the carrier, coupled barges would float on a relatively calm pool of water while also being secured to the pontoons. A high bow would deflect waves around the sides of the craft.
Specially designed, motion driven small intakes and outlets in the submerged wave deflector would restrict the volume of water that would flow through the mobile pool on which the barges float as the carrier sails through rough waters. The sides of the pontoon carrier vessel may extend vertically upward to support a roof, the design of which would prevent waves from splashing into the pool. There may be scope for such a concept to transport barges built with ‘restricted’ hulls intended for sailing along inland waterways, to be sailed across choppy water of lakes and ocean.
A carrier built with converging pontoons at the bow may feature lock-type doors at the stern. The carrier construction may include a roof that may add sufficient structural strength to allow for a pair of tugs to couple on to the rear of the pontoons at stern. One tug may remotely control the companion tug. Alternatively, a single tug coupled to the bow of the carrier may pull it over short distances that separate the mouths of 2 x navigable rivers. A single tug may push and navigate a barge carrier built with bow doors.
There may be scope for a single powerful tug to simultaneously push/navigate one pontoon barge carrier from the stern while towing a second pontoon barge carrier from its bow. Alternatively, the pontoon barge carrier may be self-powered with a forward mounted engine in the bow and electrically driven propellers at the stern, for extended voyages at higher speed. An optional propulsion system intended for short-distance sailing at lower speed may feature vertical twin-counter-rotating Voith-Schneider propulsion units located under the converging-pontoon bow. An optional electric generator vessel coupled at the bow or stern may provide power for electrically driven propellers.
The size of the carrier will depend on local conditions. One option may combine the shallow draft of a ‘Seawaymax’ ship with the beam and length of a ‘Panamax’ size of ship. There would also be the option of coupling 2 x pontoon carriers lengthwise so as to increase the number of barges being moved over comparatively short distances across rough and choppy waters. The carriers may sail on the Black Sea, Baltic Sea, Bay of Bengal, Russian Arctic, Gulf of Mexico, Gulf of Siam (Thailand) and Gulf of St Lawrence.
Inflatable Water Technology:
The gentle pitching and rolling motions of even a large carrier sailing through choppy water could produce a rhythmical or resonant ‘sloshing’ of water in the mobile pool that could damage the barges. Even the threat of such an occurrence requires the implementation of methods to restrict such water movement. One option would be to secure inflatable bags and tubes to the inside floor of the submerged wave barrier. The bags and tubes may be pumped with water to restrict any resonant movement of water in the mobile pool and minimize any damage to barges aboard a pontoon carrier.
The concept of a pontoon-based carrier vessel that carries floating barges in a protected pool is a research concept that requires further research. There are many capable maritime transportation research people located internationally, in many nations. Efforts aimed at making a pontoon barge carrier operational and viable would enhance trade by reducing transportation costs. A fully operation pontoon barge carrier that includes a wave-protected mobile pool of water on which laden barges float, may move multiple barges with ‘restricted’ hulls from ports along one navigable river, across a large body of water to ports located along another navigable river.
Maritime transportation technology researchers have the choice of either making workable a catamaran pontoon-based barge carrier with purposefully installed holes in the hull. They are also free to discard the concept and develop an entire new method by which to move barges built with ‘restricted’ hulls across energetic bodies of water. Another option would be to develop ‘unrestricted’ hulls that may be coupled into tows or trains that a tug may push and navigate over a lake or inland sea. There are economic merits to moving barges between ports located on different, distant navigable rivers.
Harry Valentine is a frequent contributor to the Martime Executive. He can be reached at firstname.lastname@example.org.
The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.