employees – “incredibly, five of whom are still working with us today,” he added.
Stand-out features Cosmos’ planned stand-out features include: a 270m2 sun deck; a flushed foredeck that doubles as a helicopter landing area (designed to accommodate Eurocopter EC135 types) and an impressive outdoor cinema complex; a 7m pool with a glass bottom and waterfall, “that plunges from the deck above”; and a beach club with a sunken, walk-around bar, featuring onyx panels and drop-down platforms to the stern and side. Other notable interior
features
provided by Sinot will include a “spiral staircase with stainless steel detailing, that wraps around the full-glass elevator, and a spacious foyer on the main deck, that combine to form a highly desirable entrance to the boat”, Heesen says. Te yacht will accommodate 19 crew
members, spread across 11 cabins, and up to 12 guests in six cabins. Four guest suites will be built on the lower deck, while a VIP suite with adjacent private studio will be located on the bridge deck. Te master stateroom will be situated on the main deck forward. Cosmos’ foredeck will also serve as a storage area for tenders. Cosmos will also adopt the fast
displacement hull form (FDHF) concept, originally developed by van Oossanen Naval Architects, which was designed to permit higher speeds while keeping a rein on hydrodynamic resistance (ibid).
To the backbone As one might expect for a vessel of this size, and one boasting an overall weight of approximately 1,090tonnes, hitting the desired top speed presented something of a challenge. “Our first approach was to conduct
a structural feasibility study with van Oossanen, to see how it could all be done,” Cavendish said. “The combination of speed, aluminium and length required Heesen to devise new methods of bringing longitudinal strength into the design without adding extra weight to the overall structure.” This was especially the case given that the four MTU main engines planned for the yacht were set to contribute a combined weight of nearly 52tonnes, even without gearboxes, he added.
yacht will face in reality, which meant that we could then design the construction to meet those loads on the hull.”
Heesen began work on a new, patented ‘backbone’ for the vessel – described as being similar to an I-beam
As a result of this study, Heesen began
work on a new, patented ‘backbone’ for the vessel – described by Cavendish as being similar to an I-beam. “Te I section makes it far stronger than a flat metal bar – you can bend a flat bar but you can’t bend an I-beam,” he said. Elaborating on how this would function
in practice, Cavendish continued: “Te keel is a reinforced section in its own right, and this forms the bottom of the I-beam. At the top of the I-beam are the points where the hull and deck are joined port and starboard. Te bits in the middle are essentially like the flat section in the middle of the I-beam. Te result is that you have a very strong and rigid section from bow to stern. “Te strength is all in the three elements
that make up the I-beam. Tat means that the hull plating is not structural but is there simply to hold everything together – essentially, to keep the furniture in and the water out.” To progress beyond the theory, Heesen
subjected a four-piece, segmented model of Cosmos to tank tests. “Each segment was floated independently, so we could measure the forces acting between the segments,” Cavendish explained. “Tese measured forces were then scaled up to determine the bending moment that the
‘Project Cosmos’ has seen Heesen make good on its pledge, two years ago, to develop bigger and bolder yachts
Energy optimisation As mentioned, the yacht will be fitted with four MTU 20V 4000 engines, generating 3,540kW apiece and driving two controllable-pitch propellers. “We have two engines linked to one gearbox, which means that two engines are used to power each shaſt,” said Cavendish. Tis set-up means that the owner can fire up all four engines when pursuing “that magic, 30knot top speed”, before easing into two-engine (and fuel-efficient) mode for lower speeds, with one engine driving each shaſt. Cavendish continued: “Feeding
four engines into two gearboxes is not revolutionary in itself, but it is certainly a first for Heesen and is relatively unusual in the conservative world of yachting.” Heesen is now conducting propeller performance tests at Rolls-Royce’s facility in Sweden. With effiency and manoeuvrability
in mind, Cosmos will also likely benefit from the installation of Promas rudders, Cavendish announced. “Te rudder has a twisted leading edge, optimised to the flow from the propeller,” he said. “[Tis] means that some of
the swirl energy
in the slipstream that is normally lost is converted into additional forward thrust.” As well as considerably enhancing manoeuvrability, this could lead to a 2-6% boost in propulsive efficiency, thereby reducing fuel consumption and related emissions – and guaranteeing that, while her guests enjoy an out-of-this-world onboard experience, Cosmos does her best to minimise her impact on the world around her. SBI
Ship & Boat International November/December 2018
33
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