The Ferrari That Made Waves: Prancing HorsePower


Its cars are adored on all corners of the globe and are seen as the ultimate status symbol for the rich and powerful. But as these incredible pictures show, Ferrari is not just a talented car manufacturer. This astonishing Ferrari speedboat set an unrivalled world record in 1953 and is now set to fetch £1.5 million at auction. The legendary ARNO XI Hydroplane craft was the brainchild of wealthy boat privateer Achille Castoldi who had a desire to break a world water speed record. He persuaded the great Enzo Ferrari to lend knowledge and technical assistance in building the ultimate powerboat. The result was a 12-cylinder, 4,500cc, V12 Ferrari engine – the same as can be found in the Type 375 Grand Prix car.

In October 1953, ARNO XI travelled at 150.2mph on Lake Iseo in northern Italy, setting a world speed record for an 800kg boat that has still never been broken. When Mr Castoldi was finished with ARNO XI, it was sold to Nando dell’Orto, a rich engineer, who went on to race it with great success for more than 10 years, securing numerous wins. The boat went through various aerodynamic improvements during that time, including a modified nose and the addition of a fin. It finished its competitive racing career in 1960 with a European championship victory and numerous fastest laps, many of which still exist.

“It is the only one with a motor from a prestigious racecar”

The hull of the San Marco Ferrari raceboat is constructed from solid mahogany longitudinal struts (like a keel), laminated mahogany members (laid transversely) and mahogany plywood for the deck. The body is in GRP. Although most competitors were using aluminium, San Marco was a pioneer of the use of moulded glassfibre on boats as early as 1955/56, which at the time was as high-tech as carbon-fibre is today.

The San Marco Ferrari was one of the so-called ‘three-point’ designs that dominated powerboat racing from the Second World War to the mid-1970s. Their typical hulls were designed with two wide sponsons at the front while the rear ended with a narrow transom supporting the propeller and rudder mounts. Therefore, at full speed the hull was in contact with water on only three zones: the extremities of the two sponsons and the tip of the propeller.


Cooling is a crucial point. The engine coolant is fed by a 4½ gallon (20-litre) buffer tank with a heat exchanger to heat lake water collected by a dynamic scoop under a forward sponson, which is only effective at speeds above 25mph (40km/h). The raw lake water must be heated before flowing into the engine. The pilot achieves this by revving up to 6,000 rpm and adjusting the clutch to get all the required torque to the propeller, which is rotating at the same speed as the motor. Ideally, the lake surface should not be too flat: small ripples can even help to lift the hull off the resistance of the water at about 50mph (80km/h). Then the boat becomes a hydroplane, running faster and faster, as Monzino liked to drive it.

Monzino’s offices were in Milan, but he often resided in one of the most beautiful villas in the world, the Punta del Balbianello on Lake Como, the site of various Bond films, including Casino Royale. From the private dock, the servants loved to watch him, impeccably dressed, climbing into his red speedboat, firing up the V12 and speeding towards Como. Less than 15 minutes later, he would alight at the yacht club where his four-wheeled Ferrari awaited to whisk him off to Milan. The only race he took part in was the Pavia-Venezia event, which, at the time, was the longest of its kind in the world.

Ten years later, in the late 1960s, Monzino was using the boat less and less. The red racer was almost abandoned when a young student of The Accademia di Belle Arti di Brera (the fine arts college in Milan), who also lived around Lake Como, discovered the strange machine and was bewitched by its aesthetics and power. This was in May 1969 and Italy was experiencing the same explosive events that France and others had witnessed a year earlier. Monzino reluctantly agreed to meet this young man by the name of Dody Jost. Finally, the deal was done and the young enthusiast took delivery of the boat, by then in great need of restoration.


The classic three-point hulls are delicate and one doesn’t launch a raceboat with an F1-derived V12 Ferrari on the water without taking certain precautions. Jost, who now owns the Nautilus hotel located on Lake Como with its private dock, protected his treasure for a few years before starting its full restoration. The hull was entrusted to Luccini, the reputed Como competition boatyard, and the engine went to Diena & Silingardi Sport Auto workshop, the well-known Modena-based Ferrari specialists.

Piece by piece, all the elements of the racer regained their strength and beauty, but the process still required years of effort before reaching original perfection. Recently exhibited at the Museo Casa Natale Enzo Ferrari in Modena, the San Marco V12 fascinated not only the public, but also the historians of the Maranello factory. For years they have paid little attention to the presence of the “Il Commendatore” engines on the water in the late 1950s. However, in 2012, the Ferrari Classiche department, which is responsible for the authentication of the most outstanding Ferraris, made the trip to survey the boat. After a detailed examination, its engine received its official stamp of approval, thanks to its historical “matching numbers” originality.

You do not mess with the experts at this level because the stakes are incredibly high. Collectable Ferraris with an exceptional pedigree can reach sky-high prices at auction. Thus, the 375MM No 0320AM (“younger sister” of the 0318AM), recently found a buyer for nearly 10 million euros at RM Auctions’ Villa Erba auction in May 2013.

But that does not disturb the serenity and pleasure that the driver has experienced since he purchased this red racer more than 40 years ago. He keeps the adventurous spirit of Monzino alive on the same lake at full throttle, where only passion and taste for excellence has guided the hand of a then younger amateur and art connoisseur without any ulterior speculative motive.

The San Marco Ferrari racer belongs to the 800kg category, which evolved to 900kg and then 1200kg towards the end of the “three point” era in the mid-1970s. The dimensions of these craft were impressive for the time. Smaller racers were powered by Alfa Romeo or BPM 2-litre engines or less, whereas these 800kg “monsters” had 4- to 6-litre engines, and sometimes even more.

“Driving was a delicate operation requiring a lot of concentration and faith because to go fast the hull must hover to avoid contact with the water, except for the extremities of the lateral floaters and the rear propeller. The engine torque is critical because, when starting up, the boat behaves like a mono water-skier. The fast engine response is essential to get the boat to lift out of the water. The heavy-duty engine racers were equipped with BPM or Maserati V8 engines; this Ferrari V12 delivers less torque at lower revs. This is where the multi-disc clutch is crucial to help transfer maximum torque to the propeller.


“The hull of a racing hydroplane is built to go fast; it is much more manoeuvrable when it is gliding across the surface of the water. The profile of the rudder is designed for high speeds and responds immediately to the slightest input at the wheel, which requires a lot of concentration on the part of the pilot. The super-cavitation propeller is only half immersed in water and the pilot can hear its characteristic roar at full throttle. Here, the torque of the propeller rotates in a clockwise direction and tends to turn the boat to the right.

This is why a small winglet is fixed under the left sponson to help the boat turn in that direction. At the time all race circuits turned counter-clockwise around the buoys. Attacking a turn around a buoy is very tricky because it requires the pilot to reduce speed, but not by too much to prevent the hull from sinking back into the water, which would result in bringing the craft to an abrupt halt.

“It was a great sport and the powerboat champions had no cause to be envious of their colleagues on the race track in terms of courage, strength and sense of anticipation. However, like car racing, you can recover on a straight stretch, easing the acceleration to maintain 6,000-6,5000rpm and attain maximum speed.”

Article by: Dody Jost