King of the Beasts
Mangusta moves into fast displacement territory with El Leon, the first in its Gransport 54 series.
Mangusta is best known for what the Italians call Maxi Open yachts: arrow-slim and ferociously fast fiberglass cruisers. At the top of the pile is the 40-knot Mangusta 165, generally regarded as the quickest 50-meter boat on the water. But times are changing. Owners who want high performance now also expect more comfort, lower fuel consumption and longer range. Combining all these features is a hard ask, one that Mangusta has spent the past five years or so working to resolve.
The result is a new flagship. The Gransport 54 El Leon is the first 177-footer (54-meter) in an all-aluminum series of fast displacement yachts. Tellingly, she was delivered to the repeat owner of three Mangusta Maxi Opens.
“The top requirement was to create a yacht over 165 feet that could reach a top speed of around 30 knots, but was also capable of efficient cruising at low speeds,” says Francesco Frediani, Overmarine’s commercial director. “We began a series of in-depth studies to research how best to achieve this target, and together with naval architect Pierluigi Ausonio came up with what we call the Fast Surface Piercing Hull. This is basically a round-bilge hull form with bulbous bow that cuts through the sea surface without planing.”
El Leon’s hull form was optimized using computational fluid dynamics and tank testing to provide a top speed of 30 knots with relatively low installed power. But she also has a transatlantic range of 4,200 nautical miles at 12 knots, and 3,500 nautical miles at 14 knots. In other words, the Fast Surface Piercing Hull (FSPH) combines the range and comfort of a full-displacement yacht with the speed of a semi-displacement design. In December, El Leon became the first Mangusta to cross the Atlantic on her own bottom when she transferred from the Mediterranean to Barbados.
“El Leon behaved outstandingly, confirming the seakeeping features of her hull I had already appreciated during our summer cruising in the Med,” says her captain, Paolo Bozzo Costa. “The yacht impressed us with her great comfort, stability and performance. I kept up an average speed of approximately 14 knots, something very few boats can achieve, and reached the Caribbean with enough fuel in our tanks to enjoy our first cruise.”
The yacht’s propulsion package is the result of efficiency tweaks throughout the Mangusta range. The Mangusta 165, for example, used to carry three 4,610-horsepower MTU 4000 engines coupled to water jets. These engines, originally intended for commercial applications, were big, heavy and fuel hungry. More recently, the Mangusta 165E (the “E” stands for evolution) was fitted with four 1,600-horsepower MTU 2000 engines, which are specifically designed for use on yachts. They are much lighter and more fuel efficient, with only marginal loss in terms of top speed.
The Gransport 54 has the same 1,600-horsepower, four-engine configuration, but with shaft-driven props instead of water jets, which are less efficient at low cruising speeds. Apart from occupying a smaller footprint in the engine room, the lighter engines also allow for better weight distribution without the need for ballast tanks. Humphree Interceptors are used to finetune the trim.
The Gransport 54 El Leon is the first 177-footer (54-meter) in an all-aluminum series of fast displacement yachts. Tellingly, she was delivered to the repeat owner of three Mangusta Maxi Opens.
‘The top requirement was to create a yacht over 165 feet that could reach a top speed of around 30 knots, but was also capable of efficient cruising at low speeds.’ — Francesco Frediani
A Mangusta Gransport 45 currently in build at the shipyard in Pisa, Italy, will carry a variant setup of three MTU 2000 engines and a Rolls-Royce KaMeWa water jet. Two engines drive propeller shafts, while the central unit is coupled to the water jet. Expectations are for a top speed of 26 knots and a range of 3,500 nautical miles at 11 knots or more than 1,000 nautical miles at 20 knots, as well as quiet nighttime cruising and enhanced maneuverability using just the water jet.
“It all boils down to the power-weight ratio,” says Nicola Onori, Overmarine’s chief engineer. “To build fast boats, you want light but powerful engines. Lighter yachts also mean more speed for less fuel, which in turn means lower emissions. In combination with the FSPH, we believe we’re at least 15 percent more efficient than our competitors. Moreover, four engines provide better redundancy, and the yacht can run on three or even two engines in an emergency.”
Other fundamental design elements in the Gransport concept are low draft for cruising in the Bahamas and Florida, and reduced noise and vibration. A 3-D model of the vessel was generated using statistical energy analysis, while a global finite element model was produced to capture high and low frequencies. Preliminary noise
levels at 20 knots were 55 decibels in the owner’s suite and 53 decibels in the main salon, according to the builder. That’s about as loud as background music or a leafy suburban street.
Having four propellers helps distribute the power more evenly, but to prevent increased cavitation the yacht has low-wake seawater intakes, and exhaust outlets that don’t interfere with the flow around the props mounted on single shaft struts.
Despite her long-range vocation, El Leon’s fluid exterior lines lack none of the feisty spirit of the Maxi Opens. Italian designer Alberto Mancini, now responsible for the styling of all Mangusta models, created an aggressive yet graceful profile that is arguably the most satisfying and balanced of any Mangusta to date.
Mancini also devised the interior design around the owner’s desire to use his yacht for family holidays and working on board. The custom layout includes a private office and deployable terrace in the master stateroom. Four guest staterooms and a gym are on the lower deck. For outdoor relaxation, there’s a beach club with a fold-down transom door and side platforms aft; an oversized forward garage with gull-wing doors; and
a hot tub on the foredeck big enough for a small crowd. According to the builder, there is close to 3,000 square feet (278 square meters) of alfresco living space.
Compared with the yacht’s dynamic exterior styling, the interior design, based on high-gloss walnut and ebony joinery with satin-finished teak soles, is soberly restrained. Hermès and Rubelli wall coverings and textiles decorate the staterooms, and loose furniture is by Minotti and Dedar.
In terms of performance and engineering, El Leon represents a decisive step for Mangusta as it ventures into the innovative fast displacement market, and takes on aluminum specialists like Heesen in the process.
“Everyone is a competitor these days,” says Frediani. “Our clients tend to be knowledgeable owners and naturally they study the market carefully before making a decision. But we believe the Gransport concept is not just another fast displacement design, and the technical lessons learned from this first example will definitely influence our future production.”