Winner of ultimate explorer tender design challenge revealed

22 January 2021

H2 Yacht Design’s 20 metre expedition tender Extender 65 has been crowned the winning concept of BOAT International’s online design challenge.

The London based studio went head-to-head with Miami based studio Radyca answering a brief that called for the perfect tender to accompany a new 150 metre expedition vessel.

Radyca's Cybertender

The fictional client was seeking something “rugged, gadget-packed and even maybe amphibious” to facilitate their adventures. With a maximum size of 20 metres, the concept had to be designed to sit in a well on the foredeck of the mothership.

Radyca presented its concept Cybertender, which was envisaged as a “collaboration between Radyca and Tesla to create a… fully electric amphibious vessel equipped with electric amphibious toys ready to conquer any terrain.”

The design featured retractable tracks for climbing up beaches and ample deck space for storing PWCs and dirt bikes.

But it was H2’s Extender 65 concept which pipped Radyca to the post.

The amphibious design features four large retractable wheels with airless tyres capable of traversing inhospitable terrain. At sea, the tender operates as a dive boat, limo tender and viewing platform rolled into one, with fold-down bulwarks, sunbeds and a fire pit on deck. Inside there is seating for 12 in a comfortable saloon and forward observation lounge.


H2 Yacht Design's Extender 65

When on land the Extender’s innovative hybrid power system would provide a top speed of 30mph, with toys like snowmobiles deployed with a rear-mounted crane.

H2 founder Jonny Horsfield explains how he approached the brief. “The first image that came to mind for expeditions with an explorer yacht were ice covered north and south poles.

“It felt natural to offer the owner and his guests or perhaps visiting scientists a vessel that would enable them to explore not just the sea but the ice-covered inhospitable land as well. Of course, nothing to say that this vehicle wouldn't handle sand dunes equally well.”

Horsfield pointed to the central sunbed that converts into a firepit for colder evenings as his favourite feature on board.

“We managed to make it look equally good inside as well as outside the water and we think the same goes for practicality. It offers all the features of open tenders, limo tenders both on water and land,” he adds.

Despite being conceived as “an imaginary fantasy vessel”, Horsfield asserts that the design is “perfectly buildable”, hinting there may be a future for the concept yet.

“We think it would actually be far less complex to build than a yacht,” he explains. “The wheel suspension could be 'borrowed' from construction machinery while the heavy rubber tires could be replaced with lightweight airless wheels.”

Additionally, there is plenty of space to “install batteries, fuel cells or emergency fuel efficient micro turbine generator packs,” he says. “We would love to see it on the water one day!”