It is hoped that finding the boat will solve the mystery of what happened on Loch Awe, Argyll and Bute, in 2009.
The search, which is to begin next month, has been made possible by the donation of sophisticated radar equipment to the loch's volunteer rescue organisation, Lochwatch, which was formed after the tragedy.
Families of the victims are to visit the loch around the fifth anniversary of the incident on March 21 and meet the rescuers, who hope to have found the boat by then.
The radar is being fitted this weekend to Lochwatch's 18ft patrol boat and, after trials, it will be used to seek out the sunken wreck using a 3D sonar feature of the equipment, which has been made possible by a £2800 donation from the MacQueen Bros Charitable Trust.
In 2011 a Fatal Accident Inquiry found the men who drowned in Scotland's longest loch had been drinking, were poorly equipped, and had not take safety precautions.
William Carty, 47, his brother Steven, 42, Thomas Douglas, 36, and Craig Currie, 30, all from Glasgow, fell from a small boat in the early hours of March 21, 2009. Their boat is believed to have capsized in heavy fog as they returned from a pub on the other side of the loch.
The alarm was raised by a fifth man who had stayed behind at their campsite.
The inquiry, under Sheriff Douglas Small, took place at Oban Sheriff Court between June 2010 and January 2011. Publishing his findings, the sheriff said he could not make any specific findings about what caused the incident because the boat had not been recovered.
He said, however, that the deaths might have been avoided if the men "had been wearing fully functional and properly secured and fitted life jackets".
Iain MacKinnon, chairman of Lochwatch, said finding the boat was "the missing link" in solving the mystery of what went wrong.
"Finding the engine would be particularly useful - then we would know if it was too heavy, etc, for the boat, contributing to its sinking," he said.
"Families of the fishermen are coming to meet us to mark the fifth anniversary and it would be good to have found the boat by then.
"We need to have this equipment working fully by the start of the fishing season on March 15.
"We have plenty of time to try and find the boat - we have a good idea where it might be from reports and talking to people. It would be the missing link. It would answer a lot of questions. We will do our best."
At the inquiry the sheriff highlighted that the then Strathclyde Fire Service boat "was not equipped with physical markers to assist in identifying accurately those areas of the loch where debris and the bodies of Craig Currie and William Carty had been retrieved".
Sheriff Small recommended police set up a "register of local assistance" including the names of people and equipment that can be called upon in an emergency rescue situation.
Mr MacKinnon said Lochwatch can now call on nearly 100 volunteers.