Three drivers of vaporetti (water buses) and a water taxi driver are on a fast-track trial for the crash that killed Joachim Vogel, who was enjoying a gondola ride with his family when he was flipped into the canal and crushed between boats.
The accident, which saw Vogel, a 50-year-old criminal law professor from Munich, thrown overboard along with his wife and three children, was caused by a series of mistakes made by the four defendants in an overcrowded waterway, prosecutor Roberto Terzo said.
Vogel's daughter, aged three at the time, injured her head and face in the crash.
A fifth person, gondolier Daniele Forcellini, faces a separate trial. He is accused of setting off the tragic chain of events by performing an illegal manoeuvre out of a minor canal onto the major waterway.
Terzo demanded the heaviest sentence - one year and five months - for pilot Riccardo De Ambrosi, the Corriere del Veneto daily said.
De Ambrosi is accused of swerving to avoid Forcellini's gondola, putting the vaporetto he was driving on a collision course with another vaporetto - the one which then hit Vogel's gondola.
Terzi called for Manuele Venerando, the pilot of the vaporetto directly involved in the collision, to serve a year in jail, while he demanded eight months each for the remaining two defendants for their roles in causing the crash.
Venice imposed new rules for boats riding through its famous canals following the death, with gondolas fitted with number plates to identify more quickly those speeding or committing other infractions.
The stripe-shirted, boater-hatted gondoliers - a powerful lobby in the city and a draw for tourists - won an exemption, however, from a rule to carry GPS locators, arguing that their low speeds would have rendered the technology useless.