Taking a gondola ride down Venice’s canals in a must for most tourist visitors to the city, but questions have been raised over their safety after four Spanish tourists took an unexpected swim last Wednesday when a wave caused by a large motorboat capsized their gondola, Italy’s ANSA news agency said.

The holidaymakers were quickly rescued by other gondolas gliding nearby, but the incident has reignited debate over the difficulties gondolas face on the waters surrounding the picturesque Italian city.

The flat-bottomed tourist boats are a Venetian fixture, frequently hired by tourists looking to explore the city’s canals but they are vulnerable to the sudden wash from passing motorboats.

“The problem remains the movement of the swell caused by motorboats,” the head of a gondoliers association Aldo Reato said, adding that he has been complaining about the problem for two years.

“There are solutions,” he insisted.

Reato explained that most incidents happen near the jetties where gondola passengers board, and that extending the boarding decks further out into the water could help protect the gondolas from any turbulence.