Back in the 1950s Ferrari powered a unique hydroplane called the Ferrari Arno XI Racing Boat and built for one thing: breaking the World Speed Record on the water. Achille Castoldi, a racing champion, proposed such a boat to the one and only Enzo Ferrari who agreed to help him in the endeavour.
Arno XI was built to shatter the speed record in the 800-kg class. Achille Castoldi had been setting records on the water since 1940. To achieve the speed record, he commissioned Cantieri Timossi to build a 3-point hydroplane from hardwood, covered in a mahogany veneer. When Enzo heard he had painted the upper body in Ferrari Red, the Scuderia F1 team was sent to lend their expertise. This culminated in a world record in the flying kilometer: 150.49 mph, which still stands to this day.
The only speedboat ever to be powered by a Scuderia Ferrari F1 engine is now up for sale and if you have to ask how much it costs, you probably can’t afford it.
In 1952, Italian speedboat racer Achille Castoldi set his sights on the water speed record for an 800kg boat. In order to achieve it, he commissioned a new three-point hydroplane from the Cantieri Timossi boatyard on Lake Como and set about finding a suitable engine supplier.
Having lost an Alfa Romeo engine deal to main rival Mario Verga, Castoldi had planned to use a Ferrari engine, so he purchased a 4.5L V12 that was identical to the “Lampredi” engine used in the Ferrari 375. With 385bhp lurking under its Rosso Corsa engine cover and a mahogany veneer covering its wooden hydroplane, Arno XI was primed to chase the record it had been built for. Initial test runs in January 1953 saw Castoldi record an unofficial top speed of 124mph, but it soon became clear it wouldn’t be enough as Verga set a new 800kg record with a two-way average of 140.74mph.
Unperturbed, Castoldi was introduced to Enzo Ferrari by his racing driver friends Alberto Ascari and Luigi Villoresi. Ferrari had not built an engine for nautical use before, but legend has it that he did so because he was impressed by Castoldi’s efforts to hide two Alfetta 158 race cars from German forces during the Second World War. Enzo sent his Chief Engineer along with an F1-specification V12 Tipo 375 engine. The result was the unique Timossi-Ferrari Arno XI Hydroplane.
Stefano Meazza and a few of the Scuderia team members soon realised that they needed more power. Using lessons learned on the track, they nearly doubled the compression ratio to handle methanol. A hotter spark was needed, so the distributors and coils were replaced by twin magnetos. Each cylinder had twin spark plugs to ensure a clean burn. It wasn’t enough, so two giant superchargers were driven by the crankshaft. Each one had its own Weber 4-Barell modified to introduce the methanol into the engine with an air/fuel ratio of 5:1. What started at 385 horsepower made between 550 and 600 in race tune.
On October 15, 1953, Castoldi made a new record attempt on Lake Iseo, achieving a two-way average of 150.19mph over a flying kilometre — a record that still stands 66 years later.
Once he broke the record, Castoldi built another boat for the 1,700kg hydroplane class. However, the engine exploded and this combined with the death of Vega in a separate accident saw Castoldi retire from racing. In 1958 the Arno XI was sold to gentleman-racer Nando dell’Orto, an engineer who revised the aerodynamics to enable racing in circuit championships resulting in the distinctive air intake and rear fin it still has today for extra aerodynamic stability. After adding a few pounds, he came in 2nd place for the 900 kg class in 1965.
After considerable success, dell’Orto retired from competition in 1968 and Arno XI was stored in a Milanese warehouse for the best part of 25 years. Just as it was on the verge of irreprable decay, it was bought by a new owner in the early 1990s and restored to its racing prime. The V12 engine was sent back to Ferrari so that it could be converted to run on unleaded petrol and, according to the later auction papers in 2012, achieved an output of 700bhp on a test bench. It has since been seen occasionally at boat shows doing parade laps, and it led a peaceful retirement. But because it is the only boat to ever have been powered by Scuderia Ferrari, it is being completely restored by Ferrari Classiche.
Arno XI was last sold in Monaco in 2012 for a price of €868,000 at auction and has since been on display at Ferrari’s museum in Modena. This Ferrari is now for sale again through Du Pont Registry and is looking for a new owner. It comes with a well-documented history file that includes hundreds of period photographs and handwritten notes from Ferrari’s engineers. The boat is currently being certified at Ferrari Classiche, and a copy of the U.I.M. record certification that attests to Achille Castoldi’s 1953 speed record is included as well.
It is the ultimate Ferrari for the ultimate Ferrari collector.