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Tuesday, March 31, 2020 

Canadian naval architect practice Robert Allan Ltd (RAL) has experienced demand from the Brazilian offshore industry, which it says is being met by new highly specialised vessels such RAL's RAlly family.

One company working for Brazilian state-run oil company Petrobras for several years is Belov Engenharia Ltda, which has built, at its own fabrication facility in Salvador, and is about to start operating, two new RAL-designed Dive Support Vessels, Belov Amaralina and Belov Humaitá, which are currently undergoing client acceptance testing.

Based on RAL's contract design package, Belov Engenharia has developed the detailed design, construction and commissioning of the Belov Amaralina in just over 18 months, which RAL says is an outstanding feat for a newly built shipyard, which includes the construction of a new floating dock.

The vessels are of the RAlly 4000 design, fitted with DP2 system, four diesel generators, three water jet propulsors and triple bow thrusters for redundancy. The propulsion system is diesel-electric to improve efficiency when operating in lower power DP modes. The vessel is certified as a Special Diving Support vessel suitable for Unrestricted Navigation by RINA.

The 40.5m long RAlly 4000 was designed by RAL to be fitted with a ROV LARS (Launch and Recovery System), an aft mounted A-Frame to operate the diving bell, a decompression chamber to support divers, and more spacious crew quarters to accommodate 38 personnel. All of this is incorporated within a tonnage under 500 grt.

Waterjets are used to ensure diver safety. Because waterjets are typically used on higher speed vessels, extensive self-propelled CFD analysis (including waterjet tunnel flow) was performed in-house by RAL to verify resistance and thrust at the slower speeds that this design will operate at when on station.

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