Italian champion Fabio Buzzi and two British racers died in the crash late Tuesday while another Italian racer survived, the reports said citing Giampaolo Montavoci, president of the national offshore and endurance commission.
The accident happened as the vessel, some 20 metres (65 feet) long and able to travel up to 130 kilometres (80 miles) an hour, tried to break the Monte Carlo to Venice record.
Firefighters said they pulled three bodies from the submerged boat while the survivor had been thrown clear.
The vessel was nearly at the finishing line when it hit the Punta Sabbioni spit, built to protect the city’s “Mose” flood barrier, reports said.
Large boulders piled upon one another from the seafloor run the length of the spit.
The UNESCO World Heritage Site is slowly sinking — something the “Mose” (Moses) system is designed to combat.
The crash was the latest in a string of accidents in the floating city, which sees everything from tiny gondolas to speedboats and vast cruise ships across its waterways.
In June, the giant 13-deck MSC Opera rammed into a dockside in Venice and knocked into a small tourist boat, injuring four people and sending others on the pier running for safety.
A month later, the 12-deck Costa Deliziosa, nearly 300 metres long, narrowly missed a yacht while being towed out of Venice in stormy conditions.
But the hugely costly array of mobile barriers at the mouth of Venice’s lagoon has suffered years of delays, and is now only expected to be finished in 2021, local daily La Nuova di Venezia said.
