Tugs designed for emergency towage and terminal operations require powerful winches and high bollard pull to manage larger ships
Emergencies over the past three years have demonstrated the need for more powerful towage capabilities to prevent distressed ships disrupting ports.
Resolve Marine director for Europe, Africa and the Middle East, Captain Nick Sloane says tugs need higher bollard pull and strong aft towing winches to remove ultra-large container ships and Capesize bulk carriers from harm.
Tugs need to be deployed swiftly to assist ships requiring emergency towage to prevent groundings and damage to cargo, seafarers and the environment, says Capt Sloane.
Deck winches and rope of the highest possible strength and tonne pull is also required. “Tugs need more bollard pull to handle the largest container ships,” he says.
One of his latest salvage projects was in Chile, where 1983-built roro ship Coyhaique ran aground near Huichas Island en route to Puerto Montt, requiring weeks of repairs. After welding the hull, removing the fuel and cargo, tugs removed the roro ship and towed it to safety.
Resolve was responsible for the salvage project and used tugs operated by SAAM Towage and Ultratug to refloat the ship and tow it to Ecuador.
Tugs are also increasingly required to deploy oil pollution control equipment, such as booms and skimmers, using deck cranes.
Boluda general manager for offshore and salvage Charo Coll says using an experienced salvage crew is as important as having deck machinery with sufficient power. She tells Tug Technology & Business how seafarers’ competence can make a difference.
“Experienced crew can use the full capabilities of tugs and equipment,” Ms Coll says. “I would put seafarer experience first.” She says tug manoeuvrability and bollard pull are also important for salvage operations, while tugs require versatile deck equipment. International Salvage Union (ISU) president Richard Janssen says tug owners are investing in more powerful vessels and deck equipment, including winches and oil pollution control for towage and salvage projects.
“Professional salvors continue to update and renew stockpiles of equipment with a focus on future needs,” Mr Janssen says, “especially investment in our people, divers, naval architects, engineers, tug masters and salvage masters who are our lifeblood.”
Investing in deck and pollution control equipment, tug capabilities and people “enables services that saves lives, protects the environment, mitigates risk and reduces losses,” he explains.
The strength and power of deck machinery is also important when choosing tugs to support gas carriers calling at LNG terminals.
Tugs operating in LNG terminals have escort notation from classification societies. This includes escort-rated winches and equipment for towing gas ships.
Their deck equipment needs to comply with OCIMF requirements, says NYK LNG Shipmanagement deputy marine and HSEQ manager, Captain Ed Narraway.
“Tugs need escort notation with escort winches,” he explains. “Tugs need to be larger and more powerful for LNG terminal operations. They need to be manoeuvrable and have fast-reaction render and recovery winches.”
There are different methods of connecting towlines to gas carriers for escort and towage, says Capt Narraway. One is using bollards on the ship foredeck and the other is using shell, or sunken, bitts that are recesses in the LNG carrier’s hull. Capt Narraway says his company prefers tugs to use the shell bitts on carrier hulls for escort and towage because it gives better control than using deck bollards.
The operational mode of the escort tug will follow these phases: rendering and recovering the towline, controlling tension control and releasing it in an emergency. The distance between tug and ship and the towline tension should be maintained to predetermined values.
“Tugs and their deck equipment are essential parts of our operations as we cannot get alongside a terminal without tugs,” says Capt Narraway.
SAAM Towage chief executive Felipe Rioja says more tugs need to be built with Escort-class notation for terminals in the Americas. “We require more sophisticated tugs for terminal operations,” says Mr Rioja. “There is a focus on compliance with the Escort-class notation and forward escort winches.” This includes handling the brake forces and “at the same time the steering forces directly affected by the speed of the served vessel,” says Mr Rioja.
“The winches to satisfy these requirements are being requested with a proper render/recovery of the towing line at higher speeds,” he says.
In Europe, Boluda France provides tugs for Elengy’s gas terminals in France – Fos Tonkin and Fos Cavaou in Marseille-Fos and Montoir-de-Bretagne terminal on the Atlantic coast.
Elengy LNG marine expert and marine manager Pierre-Antoine Chevé says deck machinery and tug bollard pull need to be rated correctly for manoeuvring and docking larger ships in variable sea and weather conditions.
“When berthing LNG carriers, we are factoring in wind speed and direction, currents and tidal forces,” says Mr Chevé. “These conditions can impact our operations and if the winds are too strong, we need to postpone berthing.”
Higher performance requirements led Boluda France to replace 55-tonne bollard pull tugs with VB Surprise and VB Acheron, tugs with modern deck machinery and 70 tonnes of bollard pull. These 30.3-m tugs were built in Piriou Shipyards in Vietnam with fire prevention and fire-fighting systems.
For escort tugs, Tugpins and Rotortug worked together to develop the first modular caliper escort winch. This simplifies winch operations while emulating advanced render and recovery functions. This modular caliper uses a drive and brake control system and brute-force principle functions.
This is a fully electric winch that has no gearbox and uses up to 10 calipers to provide brake holding power of 225 tonnes. It can accommodate 220 m of 70-mm diameter line and has a maximum speed of 60 m/min. It has a drum diameter of 600 mm and flange diameter of 1,900 mm. It can have 5-10 motors with electrical power per motor of 7.5 kW.
Tugpins’ modular winch has multiple redundant subsystems for drives and brakes, including an advanced dynamic control to emulate higher-end winch performance.
DMT’s escort towing winches can add a double drum and additional anchor. They comprise a winch body, stainless steel drum, spooling device and hydraulic or pneumatic braking, using a single, double, triple, waterfall and in-line drum arrangements.
Escort towing winches have an open or closed foundation, grooved or LeBus drum. DMT’s come with advanced controls, video monitoring, connection packs, constant tensioning systems and oil level measuring unit.
During November 2019, DMT secured a contract to supply winches to Uzmar shipyard in Turkey for tug newbuilding projects.
Heila Cranes entered into a service agreement with Albwardy Damen on 7 November to
maintain cranes on tugs after they opened a Middle East office to support electrical and automated cranes.
Albwardy Damen installs Heila cranes on tug newbuilding projects in the UAE. Heila also supplies Damen Shipyards’ tugs and workboats. A recent delivery was for a pair of cranes for multicat Kilstroom being built at Damen’s Hardinxveld yard in Netherlands for Van Wijngaarden Marine Services. This Multi Cat 3013 design vessel will have two HLRM 440-4S telescopic knuckle boom cranes when delivered in March 2020.