The 'Bucintoro' was used by the Doge as a state barge to welcome illustrious visitors to Venice and during the symbolic marrying of the sea ceremony which took place annually on Ascension day. It was a symbol of Venice's national prestige.
Helen Job.

'When at last they entered Venice the Austrians found the city desolate. …Grass and weeds grew through cracks in the pavement of the campi; stone steps and the arches of the bridges were covered with green slime; wood rotted as the opaque waters of the canals slapped lazily against palace doors and mooring posts; … the Bucintoro, stripped of its gilt and ornate wooden decorations, which had been burned as a pile of rubbish on the island of San Giorgio Maggiore, served first as a coastguard battery ship, then as a hulk for convicts, whose grim faces could occasionally be seen from boats making their way past it in the Lagoon.'

Christopher Hibbert, Venice, the biography of a city, published by Grafton.