Even long-time admirers of Enzo Ferrari's sleek, red roadsters might be surprised to learn that he also lent his expertise to create what is still, nearly 60 years later, the fastest raceboat in its class, the one-of-a-kind ARNO XI hydroplane. Developed in 1952 by wealthy Italian industrialist Achille Castoldi and Ferrari Grand Prix racers Alberto Ascari and Luigi Villoresi, the speedy craft, propelled by a 4500cc V12, handily won the world speed record the following year. Now, carefully restored to its original condition, the ARNO XI will soon go at auction to the highest bidder - an honor that's estimated to cost the buyer a cool US$2 million (or more)!

On October 15, 1953, Castoldi's dream of winning the world record for 800 kg (1,764 lb) -class hydroplanes came true at Lake Iseo, Italy with a top speed of 241.708 km/h (150.2 mph). The Ferrari "Nautico" powerplant that propelled the ARNO XI to its record, almost identical to those used in Type 375 Grand Prix racers, sports twin superchargers, dual Weber 4-barrel carburetors, two spark plugs per cylinder and delivers an amazing 600+ horsepower. Perhaps not so remarkably, the record still stands today.

The Ferrari 375 Nautico V12 engine

When Castoldi retired from hydroplaning the next year, engineer Nando dell'Orto bought the ARNO XI, modified the bow, added a stabilizing fin and raced it successfully for several more years before its career ended in 1960. Over the last 20 years, the current owner has painstakingly restored the classic hydroplane to concours condition in preparation for its sale in Monaco this spring by auctioneers RM Europe.

"This awe-inspiring racing boat has beauty, history, provenance and performance; it simply ticks every box for any serious collector," said RM specialist Peter Wallman. "It has that alluring mix of '50s Ferrari Grand Prix car with the sheer beauty and simplicity of the hydroplanes of the period."

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