The Naval Architect: June 2020
According to Jotun, the HSS covers antifouling, condition monitoring, inspection and proactive cleaning, technical services, and performance and service level guarantees. However, it is the solution’s proactivity that Jotun indicates will contribute to reduced fuel costs, emissions and risk of invasive species transfer.
Using a reference case based on a 120,000dwt Capesize bulk carrier, travelling in what the company considers as ‘challenging conditions’, Jotun estimates that after 60 months of HSS service a vessel could save US$2,830,000 compared to the market average and reduce CO2 emissions by 12.5% (17,600tonnes).
Jotun suggests that if all ships operating in challenging conditions switched to its HSS, there would be at least a 40 million tonne reduction of CO2 emissions each year due to each vessel’s improved efficiency, with the company’s internal analysis indicating that it currently has a 25% market share for such vessels.
The HSS’s main component is the HullSkater, a robotic technology designed to proactively clean ships, developed in partnership with Kongsberg. It has been designed to work with Jotun’s SeaQuantum coating to pre-emptively remove bacteria and biofilm before macro-fouling takes place, as Tom Evensen, sales director of hull performance solutions at Jotun, explains: “SeaQuantum Skate derives from the same ‘family’ as SeaQuantum X200 and is based on an inhouse developed silyl methacrylate binder technology.”
Magnetic wheels, each equipped with electric motors for propulsion and steering, hold the device to the ship’s hull, and a motorised brush on the device’s front cleans with up to 450W power and 220rpm speed, without damaging or corroding the hull coating. The Hull Skater’s power derives from lithium battery packs with up to 4kWh capacity and only minor downtime as it can recharge within up to two hours.
“The power consumption during operations is a function of the speed the HullSkater operates in, the rotational speed of the brush, level of currents and seawater temperature in addition to a few additional influencing aspects. All experience from live testing, which kicked-off mid-2017, indicates we have sufficient battery capacity for typical missions,” says Evensen.
Connected to the operator control centre by an umbilical cable, the HullSkater can be handled remotely using a global 4G network. A series of in-built cameras and sensors provide data feedback, which assists with navigation and documents fouling on the hull. He adds: “It’s always kept onboard the vessel and we operate the HullSkater using trained, Jotun-employed Skate Operators from a remote operating center.”
Additionally, HullSkater can complete the inspection and cleaning of a ship’s hull in between two to eight hours, depending on the vessel’s size and condition. Evensen elaborates: “The inspection time is around two hours per 10,000m², followed by proactive cleaning which would be conducted at a rate of about 1,500m2/h. Given proactive cleaning, the area to be cleaned each time will be typically limited.”
Since its launch in March, Jotun has received enquiries from all maritime industry segments. “The project has entered a development stage known as ‘the final verification stage’ where we interact with carefully selected customers, under commercial terms,” he adds.
The Hull Skater has undergone an extensive developmental process to reach its final verification stage and faced challenges during its two-year trial period on Wallenius Wilhelmsen’s Talisman. “Much like major car manufacturers stress test their vehicles in artic climates we too had to test our HullSkater under conditions matching the environment it would be operating under,” notes Evensen.
Interested parties can expect Jotun to own, operate and service the Hull Skater through Kongsberg Maritime’s network, Evensen adds: “Leasing the HullSkater is not an option as the solution is based on combining high performance coating, technical service, proactive condition monitoring as well as inspection and proactive cleaning.”