Two of four big, powerful harbour/escort tugs built to designs by Canadian firm Robert Allan Ltd for the Port Qasim Authority (PQA) of Pakistan, these are very impressive vessels.
They offer 86 tonnes bp comparatively economically and, with comfortable accommodation for ten, are versatile and capable of open sea operations. Further, these tugs have considerable, and very useful, open deck space aft.
"The owner imposed very onerous liquidated damages clauses for speed, bollard pull, draught, delivery, etc. which were all satisfied through delivery of these tugs of proven high-quality and performance," Robert Allan Ltd (RAL) told Baird Maritime.
"These tugs also have multi-purpose functions, such as handling all kind of ships visiting the port, harbour and coastal towing, escorting LNG carriers, off-ship fire-fighting, assistance for external salvage operations, and assistance for conservancy services."
RAL claims there were no real difficulties with the development of the tugs because the design supplied for this application utilises a proven, unique sponsoned hull form optimised for escort operation. However, due to the liquidated damages clauses in the construction contract, all contractual performance parameters were carefully coordinated between the naval architects, the shipyard, and the suppliers.
"For instance, to make sure the tugs could fulfil the requirement of speed and bollard pull, extremely detailed CFD simulations to the propeller, its nozzle, and the tug hull form were conducted."
The additional work and their unique sponsoned hull forms, which are proven to significantly enhance escort towing and seakeeping performance, means that the tugs are ideal for escort and offshore terminal support operation. Escort forces are enhanced by the effects of the sponsons as well as by the prominent foil-shaped escort skeg forward. Roll motions and accelerations are less than half those of comparable sized "standard" wall-sided tug hulls.
Also, the design emphasises cost-efficient construction without compromising customisation to satisfy specific requirements, including those set forth by the PQA.
When asked as to the future of the North American workboat industry, RAL said decarbonisation through the vessels themselves and their support of renewable projects such as offshore wind will have significant and positive effects on the complete industry in the continent in the next five years and even beyond.
"This is already creating new opportunities for designers, shipyards, suppliers, regulators, operators, crew members and shore side staff," the company told Baird Maritime. "These innovations will also hopefully continue to be a platform to inspire further innovation and improvement going forward."
RAL said there is also a growing acknowledgement of the need to introduce tugs with increased escort capabilities and crews trained to maximise their performance.
"We believe this is and will continue to be the safest and cleanest means to keep ships safe and avoid significant damage to the environment."
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