New designs for shallow-draught tugs were revealed as operators require tugs to enter harbours and river systems with low water depths
Robert Allan has produced new designs for Mediterranean harbour operations and South American inland waterway transportation.
The Canadian naval architect produced a high-power azimuth stern drive (ASD) tug for shallow water harbour operations for Turkish tug builder Med Marine.
The RAmparts 3200-SD tugboat will have an overall length of 31.5 m and bollard pull of 75 tonnes, a moulded beam of 12.6 m and moulded hull depth of 5.4 m. Propulsion with a power rating of 4,700 kW will be installed, providing this tug with a top speed of 12 knots.
These tugs will be classed by RINA for notations for unrestricted navigation, unmanned engineroom and oil recovery equipment and have fire-fighting systems of FiFi1 class.
Med Marine said this design is a versatile, multi-purpose tug with equipment for towage, ship manoeuvring and emergency response.
In South America, Robert Allan developed designs for pusher tugs operating in the Amazon River system.
Its RApide 4000-Z3 mainline pusher tug design was used for two tugs built for Hidrovias do Brasil.
These tugs will push convoys of up to 25 barges, each filled with bulk products and with deadweight of more than 2,000 tonnes.
Estaleiro Rio Maguari in Belem, Brazil, built the tugs, HB Pirarara and HB Pirarucu, each with three Wärtsilä 8L20 main engines capable of operating on heavy fuel oil. These are connected to Schottel SRP 1215 Z-drive units. The engineroom in these 39.6-m pusher tugs have two Caterpillar C18 diesel generator sets and an additional emergency/harbour genset.
With a minimum operating draught of 2.4 m, the tugs meet ABS and Brazilian Flag State requirements.
The wheelhouse provides maximum all-round visibility with a split control station providing unobstructed vision to the foredeck working area and to the convoy of barges ahead.
During the early phases of design, Robert Allan used computational fluid dynamics simulations to optimise the hull shapes to minimise total convoy resistance.
In all cases, the Z-drives are fitted in customised tunnels designed to optimise flow and propulsion efficiency while reducing draught.
“This enabled the operator to reduce the overall cost of transportation, and increases the standards of safety, manoeuvrability and comfort,” said Robert Allan.