The Otago Daily Times reported earlier in the week that Duncan had set out from an area near the TSS Earnslaw slipway about 9.30am on Sunday on Sundance II.
He travelled several hundred metres from the slipway and then stopped in the middle of the lake.
The boat was then found unattended and drifting near the Bayview area of Kelvin Heights on Sunday afternoon.
The Police National Dive Squad arrived in Queenstown on Tuesday morning and had been using sonar equipment to wade through the dark deep waters of the lake.
Police also called on the Navy to provide more advanced sonar equipment which had the ability to search larger areas at a time.