Robert Allan Ltd Designs ATB Convoys for Aliança Navegação e Logística

Canadian naval architecture and marine engineering firm Robert Allan Ltd. said it has been awarded a contract by Rio Maguari Shipyard (Estaleiro Rio Maguari – ERM), located in Belém, Brazil, to develop the design package for an innovative Articulated Tug and Barge (ATB) for shipping containers along the coast of Brazil. These two ATB convoys will be owned and operated by Aliança Navegação e Logística (ANL), a major logistics services provider in Latin America, and part of the Maersk Group.

Robert Allan Ltd.’s engineering team, lead by Senior Projects Director James McCarthy, was tasked with developing an ATB suitable for operations along the entire coast of Brazil, including the south where the worst environmental conditions along coastal Brazil are found.

Design work started by engaging in-house experts with Computational Fluid Dynamics (CFD) and Motions Analysis experience to predict the vessel reactions to the expected conditions, which served as a foundation and guidance for our design processes. The same team performed extensive hull optimization studies in an effort to significantly reduce fuel consumption while providing excellent directional stability for the ATB convoys. Analysis was also performed using our Proteus DS dynamic analysis software package to check the pin loads at the ATB tug barge connecting pins and ensure that they were within allowable limits during extreme sea conditions.

The TRAnsfer 3800 tug will measure 37.5 m by 13 m, by 6.2 m depth, have a marine diesel fuel storage capacity of 360 m³ and a freshwater capacity of 45 m³.

Propulsion machinery will include two Wärtsilä 6L32 main engines, each delivering 3,200 kW at 750 rpm, and powering Schottel SRP630FP Z-drives with 3.4 m propellers.

The ATB connecting pins are Intercon model 34C, rated to permit the tug to stay in the notch during all loading/offloading operations by allowing relative vertical movement of the tug and barge while still connected. The fully air-conditioned and MLC compliant accommodations are designed to a very high standard for a crew of up to 14, with a spacious and bright mess/ lounge area, large cabins, and a fitness room.

The tug is designed to American Bureau of Shipping (ABS) Class requirements and for compliance with Brazilian Flag Rules (NORMAM-01/DPC) with the following notation: ABS ✠ A1 Towing Vessel ATB, Ⓔ + AMS, ABCU, BP, UWILD, PMP-CBM (Coastal Service).

Each barge will measure 130 m by 28 m, by 8 m depth, and will be able to carry approximately 700 TEUs (Twenty-foot Equivalent Unit), including dangerous goods and reefer containers, distributed above and below deck. The barges will be fitted with a 500 kW Schottel SST2 bow thruster, and generator sets capable of powering the anti-heeling system, bow thruster and reefer containers.

The barge is designed to American Bureau of Shipping (ABS) Class requirements and for compliance with Brazilian Flag Rules (NORMAM-01/DPC) with the following notation: ABS ✠ A1 Ⓔ Barge (Container Barge), ATB, UWILD, CSC, CLP-V, Brazil Domestic Service.

These two new ATB convoys will significantly improve the coastal transportation market in terms of energy efficiency, operational safety, innovation and crew comfort, the designer said.

After the construction of these vessels, ERM will have completed a total of 100 vessels designed by Robert Allan Ltd.