Robotopia: Aluminum Boatbuilding with Welding Robots

Alexandra Harin/Ophardt Maritim

Two Fronius welding torches attached to robotic arms are working on the hull of an OPH969D RIB. Welding speed of the 7-axis Kawasaki FS010Xi robots is 1.5 m/min (4.6’/min), payload is 10 kg (22lbs.) at a repeat accuracy of 0.2 mm (0.008”)

Duisburg, Germany, an industrial city of roughly half a million in the most populous federal state of North Rhine-Westphalia, is at the confluence of the Rhine and Ruhr rivers. It has been a trade hub for centuries, but more recently its fortunes were tied to the boom and bust of the region’s steel and coal industries. Like so many rustbelt cities around the world, Duisburg is re­inventing itself, aided by its location on two major waterways and by Duisport, the world’s largest inland cargo port.

Tucked away in an arm of this sprawling terminal, which handles 40 million tons of goods and 20,000 ships annually, a modern office building, with giant windows and a rakish slant to the façade, towers over the jumble of warehouses and stacks of colorful containers. It’s a clean marriage of glass and steel, spick-and-span from the ground floor all the way up to the top floor with an event space comprising leather armchairs, a view of the port, and a Bösendorfer concert piano that, if sold, might fetch as much as a decent three-bedroom house. It’s unusual for a boatbuilding operation, but then again, Ophardt Maritim, the company headquartered here, is just one of several firms in a larger business group that includes hand hygiene and electric cargo bikes. Ophardt Maritim designs and builds high-speed aluminum boats for police, military, and other government agencies, with an emphasis on precise construction employing robotic welding technology. And that is a strong asset for serial production and catnip for German engineers who love precision.

I first saw Ophardt’s efforts on display during the 2018 High Speed Boat Operations Forum (HSBO) in Gothenburg, Sweden, where the yard showed off its 9m (29.5) 60-knot rigid-hull inflatable with a capacity of 12 passengers and a top speed of 60 knots with twin V6 4.2-liter 300-hp Yamaha outboards. The company’s other models include a 7m (22.9) police RIB, an aluminum conversion from a GRP hull; a 10m (32.8) model; and the 12m (39.4) flagship, which hit the water in the summer of 2018.

Fresh Start with a New CEO

The CEO of this 24-employee operation, with projected revenues of about €4.2 million ($4.75 million) in 2019, is Michael Mathias. A veteran of the aluminum boat business, he was brought in by Ophardt in 2017 to boost the fortunes of the company; founded in 2006, it has yet to fulfill its potential. Mathias, 41, an energetic manager, previously represented Nordic brands such as Ockelbo, Anytec, and Buster in Germany through Boot & Camping, his family’s firm that merged with Ophardt Maritim in mid-2018.

“You can drive aluminum boats harder, but they still need regular maintenance,” Mathias said as we strolled across the yard where stacks of older aluminum hulls are stored. He stopped at one competitor’s boat on a trailer, a sad sight with peeling bottom paint—an object lesson in the kind of mistakes Ophardt is keen to avoid. “Even basic jobs such as prep and coating of an aluminum hull or applying paint and the protection against corrosion are specialized jobs that not everyone is qualified for,” Mathias said

Alexandra Harin/Ophardt Maritim

Cleaning seams before welding

Servicing aluminum boats is one thing, selling them to government agencies quite another, because that means dealing with large organizations with specific needs, including an often complicated and lengthy bidding process, and confidentiality. “To avoid price wars, we want one strong dealer in each region who knows the government market,” Mathias explained. “The exception is Germany, Austria, and Switzerland, which we handle directly, since we understand those clients well, including their desire to work directly with manufacturers.”

Ophardt waded into a crowded pool of competition including established brands like Zodiac, Asis, Willard Marine, Ribcraft, or Boomeranger, so I asked Mathias about his strategy. “First, we take time to do the job right,” he replied. “Second, our clients don’t necessarily shoot for the lightest boat possible but for a balance of performance and toughness. Third, quality of workmanship and stress-free assembly of the hulls are our top priorities, [so] our boats are symmetrical and precise, which makes them better and lighter than boats with a composite [GRP] hull.” He estimated that Ophardt’s 10m (32.8) aluminum boat might have a weight advantage of up to 250 kg (551 lbs) compared to a GRP boat of equal size.

Dieter Loibner | Professional BoatBuilder Magazine

A snapshot of Ophardt’s 9-Meter RIB going airborne during a test drive in Gothenburg, Sweden

Ophardt Maritim is a brand of Ophardt R&D, which in turn is part of the global Ophardt group of companies that was founded in the early 1960s by Hermann Ophardt.

But after a dozen years in business, Ophardt Maritim is still just a startup compared to Ophardt Hygiene, the group’s flagship and one of the world’s leading manufacturers of hand-sanitizer pumps. “We ship 1.2 million pumps and containers each week,” Hermann said. Across all divisions, Ophardt has a workforce of 450 and reports annual revenues in excess of €50 million ($57 million).

Dieter Loibner | Professional BoatBuilder Magazine

Hi-tech hand sanitizers with their own WiFi address

At 83, with a full head of white hair, steel-rimmed glasses, and a handshake like a pro wrestler, Hermann still keeps a busy schedule, despite his sons, Heiner and Thomas, running day-to-day operations. Ophardt senior, a hard-working, frugal, no-nonsense boss, holds strong opinions and delights in creative problem-solving. In 1952, he’d apprenticed at the mighty Krupp Steel Works with 300 other youngsters before getting a degree in naval architecture and working in that field for a couple of years. Striking out on his own, he sold ventilation and air-conditioning systems to the agricultural industry, then worked for Solvay, a big chemical firm, to sell hygiene products, but left after his unit was sold to Henkel.

Hand Sanitizers

Right around that time, his hospital pals complained about leaking soap dispensers, so in 1967 he designed and built a better one and called it Ingo-Man. “I had no idea about marketing.” He chuckled. It’s one aspect of business he detests, but he found competent help. Today, Ophardt operates in Asia, North America, and Europe, making networked dispensers that have their own IP address (to keep track of the soap supply and collect data of use frequency), and one energy-independent model that runs on a fuel cell powered by alcohol from the disinfectant.

“A little money was left over,” Hermann said with a glint in his eye, “so I went back to boats.” Ophardt started with a first-rate facility and some top-notch equipment. More than $20 million was invested upfront for real estate, machines, and personnel costs over the first six years. “Duisburg,” he said about the choice of venue, “might not have an ocean, but there’s the Rhine River right at the doorstep, which is great for testing. And if you want salt water, the Hoek of Holland [where the Rhine empties into the North Sea—Ed.] is about 230 km [143 miles] away; that’s a few hours of running downriver with the current.”

Alexandra Harin/Ophardt Maritim

A trial run sans tubes on the wintery Rhine river against the backdrop of Duisburg’s industrial waterfront

Hermann is also pretty set in his opinions. About fiberglass: “It can burn down in the middle of the ocean. Recycling doesn’t happen. It’s a bear to work with, and its strength leaves a lot to be desired.” About boatbuilding: “I thought about buying a yard and traveled around only to learn that I’d be buying a museum.” About aluminum boats: “Nobody seemed to want them, and certainly nobody knew how to build them right.”

So that’s what he decided to do, applying the lessons from his hand-sanitizer business and striving for vertical integration—just as Capt. Nat did in the heyday of the Herreshoff Manufacturing Company, thus retaining control over the process and minimizing dependence on outside vendors. Ophardt Maritim produces as much in-house as possible, buying only inflatable tubes, electric components, and motors. However, with Ophardt’s manufacturing facilities in Canada, the Philippines, and Ireland that include powder-coating and anodizing plants, the boatbuilders also enjoy direct access to the firm’s expansive infrastructure.

One important element Ophardt outsources is corrosion-resistant 5083 aluminum in thicknesses from 2mm to 12mm (0.078 to 0.47), which comes from Hydro in nearby Neuss. It contains 7% raw aluminum and 90% recyclate, with additives of magnesium and silicon. “To end up with material that isn’t stressed or rippled, it is important that the recyclate is clean,” Ophardt explained, referring to his training years at Krupp, where he learned about metal properties and additives.

Alexandra Harin/Ophardt Maritim

A shipment of 5083 aluminum arrives at the Ophardt facility

To run a production with a workforce of varying skill levels, it’s necessary to learn from the auto industry, he added. “We devised a production method that offers high precision and repeatability with the help of high tech.” Humans are still necessary, and nowhere more than during design, development, and placing parts in the jigs. But once that is complete, the boats are built faster by robots and have consistent quality that would be difficult to match by manual welding. Ophardt also holds the patent for a method they call DuplicAl, which relies on robotics and computer software to build boats with precision, regardless of size and quantity.

Ups and Downs of Robotic Welding

The stroll through the workshop of Ophardt Maritim’s R&D facility led me past CNC milling machines, presses, cutters, and extruders, and boats of various sizes in different stages of assembly. But when the robots hove into view, my notion of what an aluminum boatbuilding operation looks like received an instant update. With their long necks folded, the machines resembled raptors at rest but ready to pounce on a moment’s notice. One of them was a 7-axis Kawasaki BX200L spot-welding robot with a payload of 200 kg (441 lbs), a repeat accuracy of 0.06mm (0.0024), and an operation radius of 3.63m (11.9) horizontal and 3.42m (11.2) vertical. This machine welds frames to hull bottoms and side panels

Alexandra Harin/Ophardt Maritim

Network Technician Patrick Ochman watches a trial run of the robot arm’s travel along the welding seam

For welding the hulls of the 7m RIBs and smaller components, a smaller sibling, a 7-axis Kawasaki RS015X high-performance robot, can handle only 15 kg (33.07 lbs) of payload, has the same repeatability, works with­in an operating envelope of 3.15m (10.33) horizontal and 5.73m vertical (18.8), and welds at a top speed of 19.90mm/s (0.78/s). During my visit, a technician crew was busy setting up a brand-new system of parallel ABB IRB 6700-150/3.20 industrial robots with 150 kg (330.7 lbs) of payload to replace the old main system of two Kawasaki FS010Xs for welding large hulls and components. The two new machines represented an investment of approximately €1 million ($1.13 million) and eight weeks of installation time. (The concrete foundation for the rails had to set that long.)

Using argon and helium as shield gases, these robots hold constant the wire feed, temperature, angle, and distance of the welding torch, and can weld more than 1.2m (3.94) per minute—about four times as much as an experienced welder manages in the same period. “A robot also can weld 22 points in 90 seconds, which would take a skilled welder nearly half an hour,” Mathias added. “A faster weld produces less heat, making the aluminum less prone to bending and warping, so the hull panels stay impeccably smooth inside and out, which makes it possible to glue and fasten them.” Ophardt calls that “triple technology” and says it produces better torsional stiffness, a stronger joint, and better corrosion resistance. But that’s not the end of the story.

Ophardt argues that starting with small production runs, its system yields considerable savings in time and materials. In the company’s experience, parallel robotic welding isn’t just faster and cleaner (less splatter) than manual welding, it also produces smoother seams free of porosity and stress. Inspecting the bow of one of the 10m boats in the shop yielded visual proof: the raw seams looked less like welds and more like silicone beads. Besides, smooth welds produce less waste and don’t require time-consuming cleanup. Granted, program­ming and setting up the robots takes time, but once done, production runs much faster and more efficiently. Ophardt is also adamant about quality control, which is a given when robots do the work, because all welding parameters are constantly monitored and recorded.

Alexandra Harin/Ophardt Maritim

One of the precision bending machines on the shop floor. Engineers have to understand how each tool works to design parts that are within the operating parameters

Of course, there are other aspects of robot installations to consider: Higher upfront investment; constant control and maintenance of the machines; and demand for highly qualified personnel who program, operate, and service these systems. To get the full benefits of robotic welding, everything must be superbly precise, which requires extensive preparation. It starts with the designers, who must determine weld placement and avoid creating problems with areas that prove too difficult for the robotic torch to reach. Prepping the plates (i.e., cleaning, degreasing, and deoxidizing the edges) and exactly preassembling the parts on the jigs are also compulsory. “All our designers have to learn to work all the machines on the shop floor—the routers, the milling machines, the bending presses, and the plate cutters, so they know the possibilities and pitfalls firsthand,” Mathias said.

Optimizing Designs for Production

Following the examples of companies that have perfected preassembly systems, like car manufacturers or furniture maker Ikea, Ophardt standardizes parts that have to fit its production method, i.e., hull panels with no or very little bend.

Ophardt already had a hull design with an uncommon framing system and high-quality aluminum construction that proved their engineering abilities and the advantages of the precise robotic welding system. They also were adept at gluing and fastening frames to avoid internals showing through the exterior plates. In other words, they knew how to produce perfect welds and incredibly smooth surfaces, but they still were looking for designs that resonated with the market. Herrmann Ophardt, who had invested in a first-rate operation, understandably wanted to see results that were in line with his expectations, so the company turned to Norson Design, a firm specializing in high-speed vessels. On the upper end, they set their sights on a 12m boat capable of 70 knots that had to be designed with limited curvature and twist in the hull panels, which Norson achieved with longitudinal steps and variable deadrise. They also optimized hull shape with transverse steps and spray rails. See also: A Matter of Precision – Variable Deadrise and Longitudinal Steps.

Which brings us back to those earlier-mentioned hulls stacked in the yard. They were produced for a so-called chassis system, Mathias explained, when Ophardt built only the aluminum hulls that other shops would finish and outfit to their customers’ specifications. But the idea did not take off, because, Mathias opined, “the fiberglass guys were not ready. They had no idea what to do with a flange. They could not build jigs, and they did not have the means to turn a large hull.” But Mathias wants to continue the OEM business by offering concepts, R&D for hull designs, prototypes that also could include the building jigs, or a full production run like they did for a Spanish client, who ordered SOLAS-compliant inflatables.

Alexandra Harin/Ophardt Maritim

Ophardt can do custom builds, but aims at serial production that takes advantage of their unique capabilities

To demonstrate the philosophy that inspires Ophardt’s approach to production, Mathias drove me to Issum, nearby in the countryside, to tour the company’s compliance center for hand hygiene, where copies of hospital and emergency rooms were set up to train and teach nurses, doctors, and other medical professionals. Across the way, the CNC-Center builds special parts, including boat components like textured handholds machined from one piece of aluminum. Less sexy, but more critical are the adjustable outboard brackets that have to withstand the repeated shock loads produced by a highly revved 300-hp outboard during hard landings in a seaway.

A few minutes down the road, we popped into a different world at Ophardt e-motion, where product designers working alongside electrical and mechanical engineers were putting the finishing touches on the Cargonaut. That’s Ophardt’s name for the “SUV of e-bikes,” which can be powered by motors of up to 2,000 watts and reach speeds up to 45 kmh (28 mph) while carrying a 150-kg (330.7-lb) payload. This deluxe trike is kitted out with tubeless tires, disc brakes, a carbon-belt drive, and a custom suspension system that keeps the load upright in the turns.

Dieter Loibner | Professional BoatBuilder Magazine

Mathias and Ophardt E-Motion CEO Heiko Lange (l.) discuss performance of a cargo bike that is about to be put through the paces in the testing lab

Also in the vicinity of Issum, Mathias showed me two nearly empty warehouses destined to become the production facility and the paint shop for Ophardt Maritim once the order books demand it. It betrays Ophardt’s confidence in its business and prospects in the market for high-speed boats.

Teaching Robots and Tweaking Ergonomics

Back at the R&D shop in Duisburg the next day, I had the opportunity to watch network technician and system administrator Patrick Ochmann, who’s been at the firm for more than six years, teach one of the small robots to weld a helm seat pedestal. He entered the coordinates of the “waypoints” on the X-, Y-, and Z-axes on a handheld multi-function display called a teach pendant. “When the weld changes angle or direction, I need to add reference points,” Ochmann explained. “I write a small program that looks a bit like Turbo Pascal that manages the movement of the robot arm and all the welding parameters. Then I transfer it to the robot before I move the arm down the welding paths to ensure the torch keeps the required distance and angle, which is critical for the weld geometry.” Ochmann said he uses about eight reference points per 1m (3.28) of welding path for small parts and about 35 per 10m (32.8) for larger pieces.

Dieter Loibner | Professional BoatBuilder Magazine

Ochman preps the handheld teach pendant to dial in the three-dimensional coordinates of the welding points for the robot

It takes creativity and prescience to correctly position the pieces for welding the foundation for the seat pedestal so the robots stay well within their operation radius. There are only two welds, but both have a kink or sharp angle that changes the weld’s direction. When the new ABB system comes online, Ochmann’s job should get a little easier, because those robots can import the welding commands and the coordinates directly from the 3D design program, without going through Mastercam and Robotmaster as he had to before.

The part Ochmann set up for welding was fine-tuning the cockpit geometry and the ergonomics of the 12m prototype RIB in its final stages of construction. That day, the designers and engineers huddled around the console to fiddle with the steering wheel position, the driver’s seat, and the throttle, seeking additional input from Mathias. “My colleague Oriol Prat drew a sketch of the proposed changes that we measured before I transferred them into SolidWorks,” noted Kathrin Haarhoff, who worked in the company’s hygiene and e-motion divisions before joining Ophardt Maritim. After studying industrial design, she added an engineering degree from the Fontys Hoges­­cholen in Venlo, The Netherlands, 30 miles (48 km) west of Duisburg.

“My mission is fitting a design into the budget and optimizing it for production,” Haarhoff continued. “Visible parts are often glued for better looks [using an acrylic-based adhesive injected through predrilled holes—Ed.], except for the throttle, which we decided to fasten, because it is a critical part. Hand-welding is not an option, because it would heat the plates and warp them. There are also practical reasons for using fasteners on the side, for example to get better access for cable maintenance.” Haarhoff said they would use 4mm (0.16) sheet in the bottom and 6mm (0.24) on the top of the console. Elsewhere, frames are glued and fastened, which reduces the need for welding. “We continue to develop our practices, but we’re not dogmatic,” Haarhoff said. “It’s about finding the right combination.”

Dieter Loibner | Professional BoatBuilder Magazine

Design engineer Kathrin Haarhoff transfers measurements from her notes into a CAD/CAM program to optimize cockpit ergonomics

After she and Prat agree on the changes, the part moves into production, where the bending and milling machines are programmed. Like her engineering colleagues, Haarhoff talked about the importance of feedback from the shop and being intimately familiar with the production machinery to avoid designing parts that are difficult and expensive to make. Still, a few nooks and crannies on any boat are off-limits for robots, so expert welders are called in for those spots.

Virtual Mold

“Hull shape, including bend, deformation, and deadrise, is determined by [Norson’s] computational fluid dynamics [calculation],” said Ophardt’s head of engineering, Martin Anhuf. Working in a small shared office above the shop floor, he is only a few steps away from production. He uses SolidWorks and Pro/E software (now Creo Parametric) to make sure the designs can indeed be built with the requisite accuracy. “If a 10m boat has a deviation of 1mm [0.04] somewhere, you can bet I will get called down,” he joked. “The goal is to end up with simple parts that then are defined with a system of formulae and coordinates. The dimensions are filed in numeric form, so it’s possible to calculate changes in form or scale.” It is all about repeatability and accuracy. Ophardt calls this a “virtual mold,” and Anhuf demonstrated how this method makes it possible to scale a 12m model down to 9m. “If a boat exactly matches a 3D model, it also matches all other boats like it,” he said.

Dieter Loibner | Professional BoatBuilder Magazine

Rendering of an older Ophardt hull with the numerically defined frames and longitudinals, which are easy to change in shape or size

If this methodology seems rigid, it really isn’t. Anhuf and his colleagues like to experiment with different methods of joining a cockpit sole with the hull sides, or preassembling frames and hull plates, and even entire hulls, without a single weld. “We are able to avoid [tack welds], which make parts imprecise and [introduce] flex. Everything must fit.” Despite the nearly religious adherence to precision principles, there are always challenges, he admitted: for example, when a new part must be fitted into a welded structure that might require dealing with distortion. One important tool Ophardt uses is the massive Siegmund welding table (“Lego for engineers,” as Anhuf calls it) that has rows of holes to accommodate 28mm (1.10″) locking pins that secure parts. “Heavy plates require stronger but fewer pins, while thin plates need lighter pins but more of them,” Anhuf explained. “We don’t do precision just for looks but because it is necessary for the serial production of aluminum boats that have minimal distortion.”

  • Ophardt's headquarters has floating docks that are fit for the large tidal differences in Duisburg's harbor

To continue ramping up output, Ophardt Maritim must hustle business. The cards are dealt: an energetic CEO who knows the aluminum boat business; a place near the heart of the company founder, who loves boats and opened his wallet for the significant up-front investments; the expert designers, engineers, and fabricators; Ophardt’s street cred that spills over from the firm’s global success in the hygiene business; access to relevant expertise and manufacturing assets within Ophardt’s empire of companies; and the port of Duisburg, critical for the future of the city and of Ophardt Maritim, on the Rhine, Europe’s busiest river and a formidable supply line and convenient “in-house” test venue.

All of that amounts to a good hand. What matters now is playing it well.

About the Author: Dieter Loibner is an editor-at-large of Professional BoatBuilder.