A member of the public raised the alarm with authorities about noon yesterday when the 16ft fishing vessel had failed to dock two hours after it was expected.
Locals said 35-year-old David Irvine, of Inverbervie, is one of the missing men. He had gone fishing with his grandfather. The pair's family were waiting anxiously for news of the missing fishermen at the Harbour Bar in Gourdon last night.
The search was focusing on an area five miles between Gourdon in Aberdeenshire, where it is understood the boat set off from, to Todhead Point and two miles out in the North Sea.
The RAF search-and-rescue helicopter from Lossiemouth, Montrose all-weather and inshore lifeboats, Aberdeen all-weather lifeboat, four local fishing vessels and coastguard rescue teams from Montrose and Carnoustie are involved in the operation.
Calum McNichol, watch officer at Aberdeen Coastguard, said: "We are carrying out an extensive search of an area covering 10 square miles.
"Rescue resources were quickly on scene and we have asked vessels in the area to help.
"The sea conditions are moderate and visibility is poor due to thick fog."
Conditions were expected to improve between 3am and 4am today.
An RAF helicopter that had scoured the area yesterday afternoon refuelled at Dyce airport before resuming the search operation.
A spokesman said: "[The helicopter] is conducting a radar search in an area approximately 20 miles offshore between Gourdon and Todhead Point."
An RNLI spokeswoman said their lifeboats had failed to turn up any trace of the missing creeler after combing the initial search area.
She said: "Both lifeboats launched at around midday. They are continuing to search in the area but there is some reasonably bad fog."
The search is expected to resume at first light today.