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30.05.15 17:40
Report concerning perspective tug-barge trains and composite vessels for the Dnepr River at the XII International Symposium of mechanical engineers IS

The XII International Symposium of mechanical engineers (ISUMEL-12) took place in Lvov on 28-29.05.2015.
 
About 150 scientists from different countries (Ukraine, Russia, Poland, Spain, Germany, and Australia) participated in Symposium workout. Totally about 200 reports were presented. Symposium takes place in Lvov since 1993.
 
Marine Engineering Bureau represented report concerning concepts of perspective tug-barge trains and composite vessels od river and river-sea navigation for the Danube River. An author of the report, scientific researcher of Marine Engineering Bureau Alexander Egorov introduced the paper.
 
Growth by one and half times (up to 5.5 million tons) of cargo transportation through Dnepr River in 2014 was reached generally due to grain export. This caused revival of the shipbuilding market; shipowners and cargo owners started being interested in modern effective technical means for transportation of the maximal consignments from the river ports of the Dnepr River. Especially as the cargo traffic increase is expected for about ten times.
 
Usage of existing river-sea navigation vessels' fleet (RSNV) is ineffective due to several reasons, as follows:
 
• first of all, existing vessels are become morally and physically obsolete; mean age of all cargo vessels under supervision of Ukrainian Register of Shipping is more than 35 years, while normative operational term is 25-35 years;
• existing vessels don't conform to "Max" conception that is accepted in the international shipbuilding (i.e. Panamax, Handymax, Volgo-Don Max, etc.); so they don't use effectively way restrictions;
• practically all existing barges and part of dry cargo vessels are of platform type, so it's impossible to use them for grain transportation.
 
For large players the main objective for river-sea vessels now is a work from river terminals towards road transshipment complexes (RTC) and / or marine deep-water ports, i.e. actually ensuring of mass cargo delivery to the marine vessels. The source of such interest is mostly defined by lack of deep-water ports number and by difficulty of cargo delivery to these deep-water ports by rail or automobiles.
 
Besides, feature of work of the scheme "river terminal - RTC" is the combination of rather big river shoulder through the internal waterways and rather small (but strong influencing) marine shoulder. An ultimate goal is loading (unloading) of the RSNV from (to) on a marine vessel of deadweight up to 300 thousand tons in the conditions of port roads (RTC) or port (STS (ship-to-ship) mode).
 
Shortcomings of river-sea vessels (except composite ones) are clear from abovementioned:
 
• considerable part of the working time vessel is not under running (loading / unloading, waiting for berthing, waiting for the storage vessel readiness, waiting for bridge's drawing, etc.);
• excess seaworthiness and corresponding excess main engines capacity at river part of the voyage (capacity is defined due to ensuring of safe marine work including storm reserve); especially vessel's speed is restricted for the considerable part of internal waterways;
• in some cases it is impossibility to accept the maximal vessel's dimensions which are allowed by way restrictions;
• river loading capacity is obviously insufficient for the accepted ME capacity and crew number;
• restricted bandwidth of internal waterways.
 
Possible way of such shortcomings correction is usage of tug-barge trains and composite vessels.
 
It is clear that overwhelming part of the used cargo vessels and pusher tugboats has considerable age and is to be replaced by new fleet in the nearest future. In turn it demands a clear idea about aims, conditions and methods of working activity for new of tug-barge trains and composite vessels.
 
It was shown that the following operation models for the "Dnepr Max" type vessels are of actual type:
 
• scheme on the basis of the "rotator" one that foresees pusher tugboat plus several barges for cargo transportation between ports;
• self-propelled pusher vessel plus single barge for cargo transportation from river ports towards road transshipment complex (RTC);
• pusher tugboat plus single barge for cargo transportation from river ports towards marine ports or port of other river basin or RTC;
• pusher tugboat plus two barges cargo transportation from river ports towards RTC.
 
Marine Engineering Bureau carried out the way restriction analysis of the Dnepr River; the additional problems concerning usage of maximal way dimensions were investigated.
 
When defining the maximal possible dimensions of composite vessels, the important points are the analysis of way restrictions and vessel's characteristics for passing river turns with accounting water stream.
 
But finally, the overall dimensions for "Dnepr Max" vessels (for the Dnepr River) are defined by lock dimensions; other way restrictions set more soft requirements.
 
The following conclusions were drawn:
 
• single-line trains of "Dnepr Max" type can have the maximal possible length 270 m (by restriction of locks' chamber) while full restriction is 282 m;
• double-line trains of "Dnepr Max" type can have the maximal possible length 215 m.
 
The analysis showed that the most effective for the mixed river-sea transportations is a vessel with the maximal available (for investigated navigation conditions) block coefficient.
 
Concepts of the modern tug-barge trains and composite vessels of the "Dnepr Max" type were offered In the report; these concepts correspond to the earlier formulated operation models.
 
The norm of port's loading and unloading works has essential impact on economic efficiency, such as route length especially for operation models with the fixed cargo capacity ("self-propelled vessel" model).
 
The payback period for the composite "Dnepr Max" vessel that works towards RTC is smaller than the payback period accepted in domestic shipbuilding for dry cargo vessels.
 
The analysis was carried out taking into account heavy sea, underloading at the back running, demurrages at internal waterways that include weather waiting, lock passing, under-bridge passing, narrows passing etc.
 
The concept of the composite "Dnepr Max" looks as the most realized. "Rotator scheme" and tug-barge trains concept in a whole demands the guaranteed constant cargo flows with the developed logistic chain; but now that is problematic.
 
Result: the existing composite vessel at Dnepr River that consists of 19620 self-propelled pusher vessel and 90035 attached barge has loading capacity about 4000 t while draught is 3.2 m; same time the offered concept of the "Dnepr Max" composite vessel can transport about 9400-9500 t at the same draught. At draught of 3.60 m the new composite vessel will have deadweight about 11500 t.