Waitangi Wharf Mystery Event

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WAITANGI WHARF MYSTERY EVENT

Todays photo ex Ross Griffin and from the Jim Shaw’s collection show several woody launches rafted up alongside the Waitangi Wharf.
In terms of the date of the photo, Maurice Sharp has commented that the bridge opened in 1933 and in the photo it appears to not be finished, so the likelihood is that its pre 1933. The assembled crowed are very well dressed so the photo must have marked some occasion of note.
Can anyone help us with the event and with ID’ing the launches?