Meet The Arno XI: A World-Record Boat Powered By Ferrari

The Timossi-Ferrari 'Arno XI' Racing Hydroplane still holds a 65+ year speed record.

Maranello-built machines are not only fast on asphalt and gravel, but also through water.

A Boat That “Flies Over The Surface”

The Timossi-Ferrari 'Arno XI' Racing Hydroplane is a so-called ‘three-point design’ created by Adolph and Arno Apel in the U.S. state of New Jersey in the late 1930s. Since water is much denser than air and creates more drag on a vehicle, the objective was to make the boat fly over the surface rather than travelling through it. This revolutionary speedboat design was way more efficient than previous designs.

Achille Castoldi Sets His Eyes on a Record

Achille Castoldi was one of Italy’s best speedboat racers and a talented engineer. He started his speedboat racing career in 1940 with the original ‘Arno’, which was a 400 kg-class boat with an Alfa Romeo Type 158 as engine that set a world speed record of 130.517 kph (81.10 mph).

A series of ‘Arno’ boats followed, mostly powered by Alfa Romeo or Maserati engines. When Castoldi ended his relationship with Alfa Romeo in 1951, he sought a new engine supplier to attempt the world speed record in the 800 kg-class.

Coincidentally, Castoldi was close friends with two Scuderia Ferrari drivers: Alberto Ascari and Luigi Villoresi. The trio travelled to Maranello to order a Formula 1 V12 engine from Ferrari. The specific reason why Enzo Ferrari agreed to such an unusual racing activity is unknown, but it is said that during the Second World War, Castoldi managed to save an array of Enzo’s race cars and Il Commendatore was still very thankful.

The Lampredi Tipo 375 V12 Engine

The power unit they were after was the Lampredi Tipo 375 V12 engine. This was the same engine that powered Ferrari’s Grand Prix cars during the 1951 and 1952 F1 seasons, which proved to be a success. In 1951, José Froilán González drove the engine to victory resulting in Ferrari’s very first Grand Prix win, then in 1952, Alberto Ascari won the championship with a 12-point lead over Giuseppe Farina.

Originally, the engine made an astounding 385 bhp, but thanks to official Ferrari support – including Stefano Meazza, Ferrari’s chief engineer at the time – they managed to increase it to over 600 bhp. This figure was achieved primarily by changing to methanol as fuel, allowing for much higher engine compressions. The team also added twin-superchargers and twin four-choke carburettors.

The Arno XI Hydroplane

Via: Classic Driver

Once the boat was complete for a test run, they took it to the Campione d’Italia races in January 1953. Castoldi reached an unofficial top speed of 199.559 kph (124 mph), before going for a two-way run, which would make it count officially. Unfortunately, Mario Verga, who was Castoldi’s main competitor, set an official speed of 202.260 kph (125.68 mph), which he again broke two weeks later with a recorded top speed of 226.500 kph (140.74 mph).

Nine months later, the Arno XI was upgraded for competition. Castoldi attempted his record at Italy’s Lake Iseo on the morning of 15 October 1953. Reportedly, both Alberto Ascari and Luigi Villoresi were attending the attempt as well. Castoldi jumped in the boat, went out and achieved his objective to break the speed record in the 800 kg-class with Arno XI.

The recorded two-way average speed was 241.708 kph (150.19 mph). During the 24 nautical mile event (appx. 44.5 km/27.6 miles), Castoldi ended a very successful day with another speed record of 164.70 kph (102.34 mph). This average speed was much lower than the two-way record because of the length of this particular race.

After a few restorations and most of its life spent in storage, the record-setting hydroplane was auctioned off by RM Sotheby’s in 2012 for €868,000.

Written by Max Lammers.