How Vikal created the ultimate convertible tender for 147m Topaz

10 June 2021

Here's how Vikal created a one-of-a-kind convertible tender for Lürssen's mighty Topaz...

At 147.25 metres, Lürssen superyacht Topaz (now known as A+ ) is one of the biggest superyachts in the world. With over 12,500GT of interior volume, there’s plenty of storage space on board for tenders and toys – and she carries a formidable fleet.

Of the four Vikal tenders delivered to Topaz, the 11.25 metre convertible is arguably the most unique. “This was the first of its kind", says Vikal director Lynden Vikingur. "And perhaps the last”, he adds, given the technical challenges that accompanied such an ambitious project.

“The tender was initially commissioned as a high speed, luxury, open sports boat,” explains Vikingur as he discusses the origins of the convertible. It was only later that “the client's representative requested a convertible variation on the build.”

Following discussions about the possibility of a “soft-top”, much like a sports car, the design team at Vikal came up with a creative solution. “We suggested a technical solution involving a triple folding, carbon and titanium panelled hardtop, providing greater cover, rigidity, safety and durability for the vessel," says Vikingur. After some discussions, the client agreed and construction was underway.

The final product was an equally impressive counterpart to the remarkable mothership. Able to accommodate six guests and two crew, she is powered by two 400hp Volvo engines to a swift speed of up to 52 knots.

The folding hard-top, made with carbon fibre, aluminium and stainless steel titanium, features triple panels, and is the first of its kind to ever be built for marine use. It is digitally controlled by a PLC (programmed logic controller) system and can be converted with the touch of a button, allowing the sleek tender to offer optimum comfort for her guests whatever the weather or conditions.

But the construction of this custom model was not without its challenges. “To build a folding roof on that scale, that looked good, had adequate structural rigidity and enough digital safety systems to control the dual four tonne hydraulics running the mechanism, was no small feat,” explains Vikingur.

With over 80 input/output functions, and with elements running control systems such as accelerometers, yaw sensors, string pods and micro switches, the project required a dedicated team to work on this section alone, totalling almost 18 months in its creation.

“Pulling all those vital electronics and hydraulics together, making it work and doing it with safety (and with warranty) in a small package, was challenging,” stresses Vikingur.

But pull together they did, and the 5,000 kg tender, with its futuristic roof, plush interiors and exhilarating speeds, is a product that Vikingur says has received “very satisfying” reactions.

“As a business, we consider it to be one of our great technical and aesthetic achievements,” says Vikingur, “we hope that both the layman and expert alike, share this opinion.”