Tenderworks builds custom tenders for superyachts

Bespoke down to the smallest details thanks to 3D printing
Manufacturing & Process
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16 March 2020

The exclusive world of superyachts is normally completely alien to mere mortals, except for those who actually work in the sector, of course. Tenderworks is a Dutch shipyard that supplies tenders to superyacht builders such as Feadship, Oceanco and Lürssen.

The thing is, modern luxury superyachts are now so large - in excess of 160 metres is not unusual - that they can no longer dock at many marinas. This problem can be elegantly resolved through the use of a smaller boat, or tender, to transport those on board from ship to shore. “Megayachts are usually outfitted with two tenders,” clarifies Martin Loo, Tenderworks Purchasing Manager. “There’s an open one and an enclosed one, a so-called limousine version. Generally, the open one is used when it’s nice out and the latter primarily for evening trips or in nastier weather. Either way, the tender’s appearance and detailing must match that of the mothership.”

Beyond bespoke

Tenderworks doesn’t engage in serial production and each of their tenders is a unique creation. More than that, as soon as they finish a pair of tenders (open and enclosed), the moulds are destroyed. “In principle, Tenderworks can work for any client. Feadship is a joint venture by Royal Van Lent Shipyard and Koninklijke De Vries Scheepsbouw, and our collaboration with them is special because we’re authorised to build tenders under the Feadship name. We’re quite proud of that distinction because Feadship is known as one of the world’s leading megayacht builders.”

Tender of the year

“In 2015 we received our first order for a pair of Feadship tenders. This also got us an award for the year’s best tender from Boat International. We’ve now delivered eight tenders since Tenderworks was launched in 2015. We’re currently working on another four boats, so two sets of two. Building a pair of tenders takes us a year and a half on average.”

“The mothership’s architect generally provides us with the plans for the tenders. These plans already include such elements as the engines and the placement and size of the tanks and batteries. The desired maximum speed is also specified at this time. Achieving that in practice is our responsibility, of course. We also receive a detailed list of all the required extras such as air conditioning, audio and video installations, underwater cameras, a shower, fridges and more. The expected quality is extremely high.”

3D Printing

In 2018 Tenderworks invested in a Markforged 3D printer for composites as well as one for metals (Metal X) of the same brand. “As all our work is bespoke, it’s very useful to be able to produce the smaller parts ourselves too,” explains operator Harrie van Liere. “We use the composite printer for prototyping, but the parts produced by the Metal X end up on the actual tenders themselves. It’s true that the maximum dimensions are currently limited to 20 x 12 x 12 cm. That’s because there weren’t any larger ovens available in the past. Anyway, 3D printing offers a lot more design freedom than CNC milling, though the differences in approach do take some getting used to.”

“The Metal X uses a sort of metal-infused wire, printing the parts in layers one tenth of a millimetre thick. It’s all held together using wax, which is thoroughly flushed out in the next phase. Finally, the part is sintered in the oven. This process heats the metal molecules to just below their melting point. This way, the points of contact come together to produce strong, durable results.”

Challenges and solutions

The sintering process requires a very specific gas mixture, which led to some issues in the beginning. “The deliveries by our supplier at the time were taking up to six or eight weeks and the cost was almost nine (!) times what we’re paying now,” Martin Loo relates. “During this same period, Air Liquide investigated the gas mix’s necessary tolerances in consultation with Markforged and managed to meet them using an improved filling process. This made it possible to simplify production significantly, leading to impressive cost savings. Moreover, deliveries now take two days at most and have become much more reliable.”

“The new mix is a technical success too,” says Harrie van Liere. “The sintering oven has very strict tolerances, but with Air Liquide’s gas mixture everything works flawlessly.”

Switch to Air Liquide

“One of our suppliers recommended Air Liquide to us. We subsequently arranged for an appointment and they worked to come up with solutions to our gas mixture issues. Finally, Air Liquide presented us with a proposal that outperformed our previous solution in every way. Naturally, we agreed and we’ve collaborated very satisfactorily ever since.”

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