It is the fourth day police are searching in the Frankton Arm of the lake after Matthew Duncan (46) 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 drifted near the Bayview area of Kelvin Heights on Sunday afternoon.
Mr Duncan has not been seen since.
The Police National Dive Squad arrived in Queenstown on Tuesday morning and has been using sonar equipment to wade through the dark deep waters of the lake.
This morning, Senior Sergeant John Fookes said the team had completed searching an area about 400m by 400m.
"We have not completed [searching] the area of high probability yet, so we will continue doing that today,'' Snr Sgt Fookes said.
Police have called on the Navy to provide more advanced sonar equipment which has the ability to search larger areas at a time.
"The equipment will provide sonar capabilities that will increase the speed of the search.''
The technology is due to arrive in Queenstown tonight, if the search team fail to locate Mr Duncan today.
