3D printing for marine applications is still in it nascent phase – although ambitious projects in the US, Denmark and the Netherlands are casting light on the potential for 3D-printed vessels.
In October 2019, the world’s largest 3D-printed composite boat, the 3Dirigo, was assembled and launched by the Advanced Structures & Composites Center of the University of Maine (UMaine) after this facility had installed the world’s largest 3D printer (as recognised by Guiness World Records), supplied by Ingersoll Machine Tools. Measuring 18.3m x 6.7m x 3m – and, at the time, featuring a production rate of 150lb (68kg) per hour – the printer turned around the 3Dirigo within 72 hours: a fact not lost on local boatbuilders looking to minimise newbuild turnaround times.
The 3Dirigo was based on the composite Seablade class developed by Navatek – a 7.6m x 2.6m patrol boat with a 510mm draught. Weighing 5,000lb (2,268kg), the 3D-printed version of the boat turned out to be around 400lb (181kg) heavier than its conventionally built equivalent. Equipped with twin 150hp Mercury outboards, the 3Dirigo is capable of a cruising speed of 22knots, with the ability to push beyond 35knots. However, Habib Dagher, director of the Advanced Structures & Composites Center, stresses that the 3Dirigo is very much a demo boat, unsuited to offshore operations in its current state. Instead, demos were conducted in a wave basin at UMaine, using a wind machine. Fortunately, Dagher tells Ship & Boat International, the Center has made significant progress in the three years since.
For a start, the facility’s printer has been upgraded to produce up to 420-500lb (190-227kg) per hour, depending on the resin used. The onsite printer can produce objects up to around 30m in length, 6m in width and 3m in height – dimensions that cover a cache of small leisure/professional boats and surface/subsea vehicles.
The 3Dirigo was produced in carbon fibre-reinforced thermoplastic. Dagher says: “The materials have the same strength as ABS carbon fibre, and are 100% recyclable – if the next generation doesn’t want to maintain this boat, they can grind it up and put it back into the printer to create something else.” The printer can also produce objects in bio-based materials: for example, the Center has produced a wood-reinforced biopolymer roof mould for a superyacht tender.
Dagher points out that these are still early days for the technology: most 3D print projects will focus on the creation of moulds for boat parts for the foreseeable future. Examples include deck hatch covers, structural sections (including whole hulls) and interior/exterior flooring. The Center estimates that producing a laminated structural part via the 3D printer could reduce labour costs by as much as 70%.
“This isn’t a solution for 25m+ yachts or 90m destroyers – we’re not going to beat conventional shipbuilding methods for those vessel types,” Dagher says. “The same goes for yards that produce hundreds of similar vessels. Additive manufacturing will mostly benefit specialty vessels, bespoke newbuild projects and one-offs.”
Nonetheless, the Center is continuing to explore what’s possible in getting a 3D-printed craft onto the water. Dagher reveals that late 2022 saw the at-sea demo of an uncrewed craft, “significantly bigger than the 3Dirigo”, in the Pacific for an unspecified client. Although the details of this particular vessel remain guarded, it’s known that UMaine delivered two 3D-printed demo boats to the US Marine Corps in Q1 2022, the larger of the pair featuring the capacity to carry two 20’ containers. “We also intend to have a 3D-printed vessel capable of carrying crew and passengers operating in the Gulf of Maine before the end of summer 2024,” Dagher confirms.
RoboPrint project
Meanwhile, in Denmark, boatbuilder Tuco Marine Group has signed up to the RoboPrint project – an initiative keen to establish continuous fibre composite (CFC) 3D printing on an industrial scale. CFCs are advanced composite materials that offer superior mechanical properties (such as high strength, stiffness and improved fatigue resistance). These materials comprise continuous fibres (including carbon, glass, aramid and basalt, for example) combined with a polymer matrix, which binds these fibres together and protects them. Common matrices include resins such as epoxy or polyester.
3D printing could bypass labour-intensive composite boatbuilding methods
The goal is to develop a CFC extruder and incorporate it into a robotic printer, and then to 3D-print a full-scale boat. The four-year RoboPrint project has received DKK19.7 million (US$2.9 million) in funding from the Danish Innovation Fund, and, alongside Tuco, brings together: lead partner DTU – which, together with FORCE Technology, will develop the CFC technology; Robot At Work (RAW), which is supplying the 3D printer; and US-based Cosine Additive, responsible for developing the printer head.
Jonas Pedersen, Tuco Marine Group CEO, says that the printer can produce a boat of approximately 8m x 2.5m, based on the builder’s ProZero range of professional craft. “Currently, the production of composite boats is a labour-intensive process involving manual cutting, laying and laminating of glass or carbon fibre in a mould,” the RoboPrint partners comment. “These manual methods pose risks of material defects, require careful handling of materials [due to health considerations] and result in significant material waste. Moreover, design flexibility is limited by the need to create a mould for each new design.
“The digitalisation of the manufacturing process will also enable automated storage facilities and the production of new 3D designs. CFC 3D printing enables production of complex geometries and fibre architectures otherwise not feasible with conventional methods.”
Pedersen echoes Dagher’s opinion that, as a relatively novel solution, 3D printing may take some time to become ‘the norm’ in maritime circles, adding that it will be necessary to secure flag state and class society approval for 3D printer-produced newbuilds.
Olympic ferry
If all goes to plan, however, we could get to see a 3D-printed small ferry in action at the 2024 Paris Olympics and Paralympic Games.
A render of the 9m, 3D-printed autonomous ferry being prepared for the 2024 Paris Olympics
In April, Dutch builder Holland Shipyards Group (HSG) hosted its first “keel-printing” ceremony as it commenced work on an autonomous, all-electric ferry that will shuttle passengers across the Seine River during the Olympics. For this project, HSG worked alongside fellow Dutch firms 10XL – a specialist in XL hybrid manufacturing using recycled waste, which was tasked with producing the ferry’s hull – and Royal3D, which produced the vessel’s superstructure. Meanwhile, Amsterdam-based start-up Roboat, which co-designed the ferry, provided the vessel’s autonomous system.
The fourth partner in the project is river boat operator Sequana Développement, which will oversee the ferry’s transits between the Athlete’s Village site and the island of L’ile-Saint-Denis for the duration of the event.
The completed ferry underwent river tests in late August, HSG director Leendert Hoogendoorn tells Ship & Boat International. The vessel measures 9m in length and 3.9m in beam, and can carry up to 35 passengers – thereby capturing the 3Dirigo’s title as largest 3D-printed vessel in the world (for now). The Roboat system grants the newbuild Level 4 automation, including the ability to dock and recharge its batteries automatically.
The ferry’s hull is constructed in rUltraMarathon 3D (r-UM3D), a fireproof material made from post-consumer waste, produced by Rotterdam-based recycler Transmare CirQlair. 10XL has previously used r-UM3D to create bridges, boat components and furniture. Printing of the ferry took about 15 days, Hoogendoorn recalls. “This is because the ferry incorporates three layers of r-UM3D, to ensure that we had full hull redundancy, and because this was our first time doing this,” he explains. “In future, it may be necessary to use just one or two layers, which would shorten the production time.” One tremendous advantage of additive manufacturing, he notes, is that builders can incorporate all components (such as cable trays, ducts and benches) into the build in one hit, rather than having to spend time and money sending the completed hull to be outfitted separately.
The autonomous tech package includes two sensor hubs, installed on either end of the ferry. Ynse Deinema, Roboat CEO, explains: “These sensor hubs contain several digital sensors that perceive the environment: LiDAR, an array of cameras, RTK GPS and an inertial measurement unit. The processed data generates centimetre-precise localisation and a 3D, 360° full view of the direct environment around the vessel. Other boats and floating objects are detected, as is the docking station to which the boat connects”.
Hoogendoorn explains that the ferry was equipped with four fixed thrusters, two on the sides and two at the bow, granting the newbuild enhanced manoeuvrability in line with the “drone principle”, and he estimates that the ferry should undertake its short-hop trips across the Seine at 4knots. Beyond the Olympics, the combination of sustainable production, smokeless river crossings and crew-free operations make this one to watch for those interested in developing net-zero urban riverine passenger services.
