Late March saw the ‘end of an era’ of sorts – not to mention, a new beginning – as UK offshore wind CTV operator Tidal Transit purchased what it intends to be its last ever diesel-powered crew carrier, in line with its plans to transition to a fully electric fleet.
The 27m x 9m newbuild, Arabella Jane, was constructed by Singaporean shipbuilder Penguin International as a slightly modified version of Incat Crowther UK’s WindFlex-27 CTV class. Fitted with four Volvo Penta D13 IPS units, equating to 2,060kW of combined power, Arabella Jane also constitutes the operator’s first 24-pax-capacity vessel. “We’ve invested in our last diesel burner, which is exactly what we want to be doing right now,” Leo Hambro, Tidal Transit commercial director, tells Ship & Boat International. “We believe the tide has turned – with all the companies we work with having very clear net-zero targets, and battery technology now being deliverable, there isn’t a reason why we shouldn’t be doing this.”
It’s been a long journey, involving a significant learning curve, to get to this point. Following its formation in 2011, Tidal Transit initially pursued a new breed of CTV, capable of handling offshore wind farm runs with optimal safety and efficiency. “Whilst the initial wind farm industry was talking about converted angling boats with tyres on the front, we brought about a change of vessel type and a change of accessibility, through innovative hullforms from the Spanish sector,” Hambro says. In fact, it was Mercurio Plastics Shipyard of Cartagena, in south-east Spain, that constructed one of Tidal Transit’s first dedicated offshore wind CTVs, in the form of the 20m x 8m, fibreglass CTV Ginny Louise, which entered service in 2012.
“After we did that, many competitors came in with bigger and bigger boats,” Hambro explains. “So, we took a step back and investigated Umoe Mandal’s surface effect ship [SES] designs.” As an experiment, Tidal Transit assumed management of the 26.6m SES Umoe Firmus in 2016. “We saw the SES technology as being very valuable, especially for wind farm projects located further offshore,” Hambro recalls. “Unfortunately, technically, an SES is very complicated and difficult to maintain. When you’re going from A to B, it’s incredibly valuable for transiting at, say, 50knots. It’s when you throw in additional trips to turbines C, D and E that an SES becomes problematic, because of the high fuel consumption involved.”
However, the operator’s brush with SES deployment at least granted it a good insight into the technology: learning what doesn’t work can be as valuable as learning what does. “The experience helped us reevaluate where we should be going,” Hambro says – and so, come 2018-2019, the company had a clearer vision of the direction it wanted to take.
Leo Hambro: “The interesting thing about the SOVs built in the past five to 10 years is that there are empty spaces in the hull. These empty spaces are future technology spaces… you can easily install 10-15MW of batteries”
“We didn’t want to copy what everyone else was doing: bringing more and more vessels into the sector,” Hambro says. “We’d been forerunners in this sector, but we still needed ‘a frontrunner’: a frontrunning technology to keep our clients, and investors at HICO, happy. Because our vessels were now sitting in that older category, we didn’t have a larger, 24-pax, fully classed vessel to fall back on.”
The solution came when Penguin informed Tidal Transit of its plans to build a stock CTV, based around a Volvo Penta quad IPS system. Penguin, of course, is no stranger to hybrid- and pure-electric builds, having produced battery-powered ferries (see, for example, Penguin Refresh in Significant Small Ships of 2023) and hybrid patrol vessels, such as MPA Guardian. This chance conversation with the yard proved to be fortuitous for Hambro, ushering in the contract for the construction of Arabella Jane.
“We knew that the Incat Crowther hull shape, designed to carry 35,000litres of fuel, would provide a vast capacity for carrying batteries in the future,” he says. “For us, the Volvo Penta IPS was the best way of ensuring a retrofittable vessel. It meant we wouldn’t have to change the CTV’s propulsive system, just the energy source – and we would simply have to swap the engine for a motor. Also, we’d have all the necessary spare parts to hand.”
While Tidal Transit may now be gaining attention and accolades for its march towards fleetwide electrification, it hasn’t always been this way: Hambro remembers a time when he felt very much in the minority when advocating electric CTV adoption. “Some of our competitors have been laughing at me, saying ‘It’s never going to happen’,” he says – recalling an attitude that dogged the concept of electric vessels full stop for much of the early 2010s. However, attitudes are changing: operators including NOS and MHO-Co are now actively eyeing up electric CTV opportunities, the latter having recently bolstered its fleet with a series of China-built, hybrid-powered newbuilds.
So, why opt for electric power instead of the other alternative fuels currently in development and testing? For Hambro, the issue is fairly clear-cut. While HVO has been mooted as one way forward for smaller vessels, for instance, concerns have been raised over unsustainable, unethical palm oil production methods, and a question mark hangs over long-term availability of used cooking oil. “We don’t eat enough chips to create HVO to power ships,” he notes.
Similarly, the use of hydrogen as a fuel has attracted some operators, but Hambro counters: “The amount of energy consumed in producing, storing and transporting hydrogen makes it incredibly expensive.” Meanwhile, the problem with methanol, he says, is that “the energy density is problematic for small vessels.” He continues: “Methanol is a stepping-stone fuel. It’s by no means zero-carbon; it’s a reduction of carbon. We’re trying to avoid the ‘stepping stones’, and leap straight to where the technology allows us to today.
“While the batteries we’re putting in our boats today might not be the ‘holy grail’ that revolutionises fleet operations worldwide, in 10 years’ time they will be repurposed as quayside batteries, providing shoreside energy storage and office back-up power. We can then fit the boats with new batteries with greater energy density, giving us improved range, while the onboard propulsion system stays exactly the same.”
‘Arabella Jane’ will serve as “the frontrunner for future electric builds”, as well as Tidal Transit’s first 24-pax capacity vessel
The drive towards electric power is being mirrored by an evolution in battery-charging tech. In fact, the next few years could see CTVs (and, Hambro emphasises, SOVs) drawing electricity directly from offshore assets at the wind farm – be these substations or the turbines themselves. “In the industry we’re in, it’s very clear that if our client is producing electricity at the place we’re going to every day, what can be done electrically should be done electrically,” Hambro underlines. He cites industry developments such as Damen’s forthcoming 7017 E SOV and the new fast chargers produced by MJR Power & Automation, Stillstrom, Ocean Charger (Vard), Oasis and Apollo.
Hambro adds: “Talking to some SOV operators, they say the interesting thing about the SOVs built in the past five to 10 years is that there are empty spaces in the hull. These empty spaces are future technology spaces; even on existing SOVs, you can easily install 10-15MW of batteries, allowing these ships to run their day operations on pure electric power.” This is a particular advantage when it comes to electrifying the fleet without drastically overhauling proven vessel designs.
However, the transition will require a ‘mind shift’ on the part of crew, Hambro believes. “The changes will be small but far more evident,” he says. “When you’re looking at the tank of a diesel burner, you don’t really care about a litre here or there. However, noticing that your 100% remaining range has dropped to 30% means a lot more – as electric car owners are finding. I hate the term ‘range anxiety’, but it’s not about this: it’s about planning. If you plan properly and have the right charging infrastructure to allow you to operate for the required period, the anxiety disappears.” In this respect, personnel will benefit from more training related to energy usage, battery storage and charging times.
The other change we might expect to see, as battery power becomes more commonplace, relates to the designs of the offshore CTVs themselves. Hambro views foiling technology as a potential shake-up for the development of new hullforms, “which have become a bit static over the past few years”, he says.
For the full feature, including technical particulars and the latest on Tidal Transit’s e-Ginny retrofit project, check out Ship & Boat International May/June 2024
