Mirabella V:

When Joseph Vittoria invited me to work with him on the development of a 70 metre super sailing yacht he originally stipulated two personal requirements:  the yacht must be built in composite materials and she must have a single mast rig. 

This new yacht, growing to 75 metres so as to achieve optimum interior facilities, was designed to fulfil my client’s dream to create the ultimate windward performing sailing vessel that would allow his family as well as private and charter guests to experience a unique level of sailing that incorporated comfort and style only associated until now with the largest luxury motoryachts and cruise ships.

Composite materials, never before used on such a large sailing yacht, allowed weight savings that despite finally requiring a displacement of over 750 tonnes still allowed Mirabella V to achieve a displacement length ratio comparable with the latest racing yachts.  These dimensions could have been even more impressive had this yacht’s commercial charter requirements not necessitated MCA certification and consequently commercial ship fire insulation (steel doors, stairways, etc.) causing 60 tonnes more weight over and above already strict sound and vibration insulation specification.

Mirabella V’s hull lines were refined around this increased displacement requirement and incorporated a high aspect 150 tonnes retracting bulb keel (allowing under 4 metres draught) and twin rudders so as to present hydrodynamic design principles in line with the latest performance oriented sailing yachts.

High Modulus Engineering were commissioned to design the composite structure, carbon fibre mast and boom to DNV certification requirements.  In addition, Germanischer Lloyd were asked to certify the 90 metre mast, spreaders and boom, the largest such components ever built.  VT Shipbuilding, the English warship builder, secured the building contract for Mirabella V based on their composite minehunter systems and proven shipbuilding infrastructure capabilities.  The size and complexity of such a vessel was clearly beyond most traditional sailing yacht building organizations’ capabilities.  The final decision on materials and laminate proposals also took into account VT Shipbuilding’s production systems and the logistical requirements of building such a large structure.

VT Shipbuilding proposed laminating the hull and superstructure within a female mould and they efficiently produced these gigantic tools directly from our digital design data by way of CAD / CAM interface.  Flat panels for bulkheads and secondary structure members were laminated using VT Shipbuilding’s resin infusion process and cut  to shape via direct digital interface with the design lines.  One of the many unique procedures during the construction of Mirabella v was to laminate the main deck and superstructure in one piece, then cut it into sections to facilitate its connection to the hull.

To honour an additional client request to allow the new yacht to enter Palm Beach Harbor and a variety of shoal anchorages, a retracting keel was a necessary requirement.  The 150 tonnes high aspect ratio bulb design concept required a major design and engineering effort.  A fabricated steel fin shell incorporating a large streamlined bulb was filled with 117 tones of hot lead so as to achieve the lowest possible centre of gravity.  A single hydraulic ram provides the vertical actuation.  The bending loads for this 10 metre deep keel at a theoretical 90 degree angle of heel, together with large safety factors, the DNV minimum load case, were analysed with extensive FEA computer modeling so as to ensure full structural integrity in the most extreme sailing conditions.

Twin rudders were chosen to ensure maneuverability and directional control under any sailing conditions with the restricted rudder blade depth and to maximize the usable lazarette space for the Hinckley 29 foot tender to be housed when not ferrying the guests in comfort.

Luciana Vittoria’s extensive experience in the sailing yacht charter market had a big influence on the design of deck and interior arrangements.  Private and public multi-function areas were given equal priority so as to allow for a wide variety of lifestyle requirement for the owners’ party or 12 charter guests.  The overall practical interior design detailing and soft furnishings have been enhanced with traditional joinery and antique furniture elements.  High quality materials, hardware and interior workmanship from specialist companies ensured Mirabella V’s accommodation areas are to world class standards.  The result is a spectacularly spacious yet intimate environment for both the owners’ party and the select number of charter guests who will be fortunate enough to experience life aboard this, the largest sailing yacht of her type afloat.

During the early stages of designing Mirabella V, a carefully selected number of material and equipment suppliers were invited to be involved with this ground breaking project so as to ensure the highest possible standards were achieved in every area of specification, design and construction.  Due to the uniqueness of this pioneering project, many area of the yacht were necessarily custom and relied heavily on the creative design and manufacturing capabilities of the chosen companies.

In selecting these contributing companies, innovation and reliability were the primary requirements and the present result of Mirabella V’s operational success is a tribute to the team effort put in place to create such a unique sailing yacht.

Sail-World’s Nancy Knudsen interviewed Ron Holland recently about Mirabella V’s sailing performance.

Read Nancy’s article by clicking here.