An enthusiast for motor boat racing, Achilles Castoldi decided to focus on setting top speed records in 1953. He commissioned a 800kg class three-pont hydroplane hull to be built by Cantieri Timossi. The hull was dubbed Arno XI. As for the engine, he turned o the new up and corners of the auto racing scene – Scuderia Ferrari. On the morning of October 15, 1953, Achille Castoldi succeeded in smashing the 800 kg class speed record with an average “flying kilometer” two way speed of 150.49 miles per hour. He followed up the performance on the follow day by setting another record of “24 nautical miles” event with an average speed of 102.34 miles per hour. Arno XI was restored in the early 1990s and was placed for auction at the Coys Festival Silverstone in 1997 that was not sold. However, Arno XI was eventually sold at the 2012 RM Auction in Monaco for 1.12 million dollars.