Confederation Marine Modellers
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The Construction of modern super yachts.
The smell, the sound, the ambiance. As soon as you enter a shipyard that builds in wood, the differences are plain. Skilled craftsmen toil over intricate tasks, using techniques passed down through the generations. There is a deep emotion in wood construction,that contrasts with the mechanical nature of composite building.
One might expect this type of construction is limited to sail boats but there are a number of yards that specialise in building motor yachts out of wood. The complicated technology associated with modern motor yacht construction may seem at odds with building in wood, but there are yards that consider wood to be the finest material and which produce beautiful yachts for discerning owners who also appreciate its unique qualities.
From the outside, a modern wooden yacht can look very similar to a composite yacht. Many are classically styled to take advantage of the shape of the material, often with fewer curves in the hull and superstructure as wood does not offer the same freedom to develop compound curves. There are many other subtle qualities of wood that make it an ideal material for construction, such as its ability to absorb sound, which makes the hull quieter when under way. Wood construction lends itself to classic interiors where the structural timbers of the hull and superstructure can be emphasised.
Wood construction has changed to meet modern demands. It is rare to find motor yachts built with planking systems where the seams are caulked, except on tenders and other small craft. It is hard to get the fine, smooth finish that modern standards demand and often plywood sheets are used as a base or have completely replaced the traditional planking. However, plywood construction can limit the development of complex shapes because it will only bend in one direction. But cold-moulded construction, using high-tenacity glues, is much more flexible as the hull is built from thin strips of wood laid over a framework.
As we will see with the Aguti motor yacht, cold-moulded wood construction has been developed to a very high standard using a combination of composites and wood, which allows for a highly durable, varnished wood finish to be produced on what looks like a traditional wooden hull.
Perhaps as important nowadays, wood construction is more environmentally friendly than composite construction. The wood comes from sustainable sources, unlike composites, where the chemicals are mainly oil based, and emissions from the wood construction process are minimal compared with the styrenes used in composites.
Aguti Yachts is based on the Bodensee, an inland lake that borders Germany, Switzerland and Austria. The area has some of the strictest pollution rules in the world, which has inspired some of the yard’s many innovations for its new launch, the Aguti 20m.
Years ago, mahogany was the wood of choice for quality motor yacht hulls and the yard has resurrected this style using a new construction system to produce a lightweight rigid structure that is the equal of any composite hull.
The hull of the Aguti 20m looks stunning. The mahogany hull gives the yacht a retro feel, accentuated by the swept-back deck house with its white top and contrasting dark glass. There is a slight reverse sheer to the deck, the profile is distinctive and sporty and it is thought to be the first production motor yacht to be fitted with an exhaust cleaning system that will enable it to meet the stringent emission standards due to become law in five years time.
The lines of the hull above the water conform to tradition with a distinctive flare to the bow and a suggestion of tumblehome at the stern that is offset by a stainless steel finished rub rail extended forward from around the transom.
Below the waterline, the tank-tested hull features a deep-V hull with a 17.5 degree deadrise with spray rails and a chine line that rides high at the bow.
The hull is built on a laminated wooden keel and longitudinal stringers, and the engine beds are also formed from this laminated wood. Temporary frames are used to allow the combination wood and composite hull planking to be formed with the composite bulkheads left in place to stiffen the hull structure.The hull planking is formed from six layers, the inner and outer layers from mahogany and the central core is two layers of western red cedar. Between the layers is a laminate made of carbon fibre and epoxy resin. The hull is immensely strong and it has good sound-deadening qualities.
Wood provides additional insulation against heat, sound and vibration, making living and social areas more comfortable.
The accommodation, comprising three cabins with separate bathrooms, is roomy and the saloon’s unique design allows guests to maintain contact with the bridge, which forms a balcony within the space.A unique feature of the saloon is the way in which the whole top can be hinged upwards under hydraulic power to create a wide front opening. It is strong enough to remain open at full speed is a practical solution to deck house ventilation. There is a comfortable settee and a fold-out table in the saloon creating the main dining area, and some neat features here such as wooden handrails on the stairs and a beautiful, curved wooden ladder that gives access to a large deck hatch, providing an alternative and secure route to the foredeck.
Forward from the lower saloon is the master suite, with its separate shower and heads cubicles on each side of the passageway. The bow flare of the hull narrows the area forward and this means that the bed is set rather high.
Immediately aft from the lower galley is a single cabin that could serve either as a guest or crew cabin and has an en suite shower. Alongside, steps lead down aft to the VIP cabin, where the bed is also mounted high to accommodate a tank underneath. The interior can be fully customised to suit individual owner’s needs.
On the prototype, the interior has been kept low key with cream leather furniture and panelling combined with traditional warm mahogany. Externally, the detailing is superb with the decks covered in traditionally laid teak.
A hatch in the cockpit gives access to the engine compartment. Everything is easily accessible and the varnished engine beds are a reminder that among all the complex machinery this is a wooden boat at heart. The engines are a pair of 810 kW MAN diesels and these drive forward to the ZF V-drive gearboxes and then back to a conventional shaft and propeller propulsion system.
The Camuffo Shipyard in Italy can trace its roots back over 500 years, which makes it one of the oldest shipyards in the world. The yard was originally based in Venice and built beautiful wooden boats that sailed the Venetian lagoon and square-rigged ships for the Napoleonic wars in the early 19th century. Ownership under the Camuffo family stretches back for 18 generations.For the past 160 years, the yard has been located at Portogruaro, 40 miles to the east of Venice, in a quiet backwater that leads out to the sea. Since the Second World War, the type of craft built at the yard has changed from work boats, fishing boats and military craft to sports boats and then motor yachts for the leisure sector. But one thing has never changed: in a world that is now almost totally dedicated to the production of composite yachts, Camuffo still builds only in wood, producing some remarkable motor yachts capable of speeds up to 40 knots. The current building programme includes three flybridge motor yachts: a 55m, a 60m and a 65m.
Traditionally, the focus of much of the production at Turkish yard Vicem has been on producing wooden motor yachts for the US market, but now it has turned its attention towards Europe.
The designs are based on the New England concept of a low coachroof that runs aft into a classic superstructure shape using a semi-displacement hull with a flared bow. The result is a range of beautifully crafted designs with performance up to 30 knots.
Information taken from http://www.boatinternational.com/ where you will find additional information on this topic.