''Arno XI'' is a hydroplane conceived by . Designed to break water speed records, it was built between 1952 and 1953 by the Cantiere Timossi boatyard, located in Azzano (a

frazione A ''frazione'' (plural: ) is a type of subdivision of a ''comune'' (municipality) in Italy, often a small village or hamlet outside the main town. Most ''frazioni'' were created during the Fascist era (1922–1943) as a way to consolidate territ ...

Mezzegra Mezzegra is a former ''comune'' (municipality) in the Province of Como in the Italian region Lombardy. Since 21 January 2014 it is part of the comune of Tremezzina. Geography It lies on the northwestern shore of Lake Como between Tremezzo and Le ...

) on the shores of Lake Como. Castoldi persuaded Ferrari, via its racing drivers

Alberto Ascari Alberto Ascari (; 13 July 1918 – 26 May 1955) was an Italian racing driver and a two time Formula One World Champion. He was a multitalented racer who competed in motorcycle racing before switching to cars. Ascari won consecutive world titles ...

and

Luigi Villoresi Luigi Villoresi (16 May 1909 – 24 August 1997) was an Italian Grand Prix motor racing driver who continued racing on the Formula One circuit at the time of its inception. Biography Born in Milan, Lombardy, and nicknamed "Gigi", he was the older ...

, to supply him with the same power unit used in the

Ferrari 375 F1 :''See also the 340 and 375 road cars sharing the same engine'' After finding only modest success with the supercharged 125 F1 car in Formula One, Ferrari decided to switch for 1950 to the naturally aspirated 4.5-litre formula for the series. ...

. The engine was installed in a Timossi three-point racing hydroplane hull. Castoldi managed to further increase horsepower by attaching two superchargers. The result was a 502 bhp speedboat, which he used to hit a 150.19 mph top speed in October 1953 on Lake Iseo. This world speed record for an 800 kg boat still stands today. A similar hydroplane was constructed by

Guido Monzino Count Guido Monzino (2 March 1928 – 11 October 1988) was a twentieth-century Italian mountain climber and explorer. In 1973, he led the first Italian expedition to climb Mount Everest. He was the son of Franco Monzino, who founded the ...

in 1954. Like ''Arno XI'', it utilizes a Lampredi engine, in this case sourced from a wrecked

Ferrari 375 MM :''See Ferrari 375 F1 for the 375 used in Formula 1 racing, and 375 America, a GT car'' The Ferrari 375 MM, was a sports racing car produced by Ferrari in 1953 up to 1955 for the road cars. It was named "375" for the unitary displacement of one ...

Today

''Arno XI'' was later sold and raced in numerous competitions, finally retiring in 1960. It has since been restored and is expected to go for up for sale by RM Auctions for up to €1.5m. In 2021 the ''Arno XI'' is for sale again at an asking price of USD$12 Million.

References

{{Ferrari Racing motorboats Hydroplanes Ferrari