Mayo RCMP Const. Michael Potvin, 26, has one year of service with the police force. He has been missing since the police boat he was in capsized Tuesday night. (RCMP)RCMP divers are on their way to Mayo, Yukon, to help search for an officer who has been missing since a boat capsized in the Stewart River on Tuesday night.

Const. Michael Potvin, 26, was one of two Mayo Mounties in an aluminum RCMP boat when it capsized just before 8 p.m. PT.

Potvin was trying to swim to shore when he disappeared. Police say he was not wearing a life-jacket.

"We remain optimistic and hopeful that Const. Potvin will be found downstream safe," Sgt. Don Rogers told reporters Wednesday afternoon in Whitehorse.

"However, we are realistic and we recognize that as more time goes by, the likelihood of his survival lessens."

Encountered engine problems

Potvin and the other officer had taken the boat on a maintenance run when they encountered problems with the motor.

They were headed back to the local dock, working on the motor along the way, when the boat suddenly took on water and capsized, Rogers said.

The other officer clung to the overturned boat while Potvin tried to swim to shore. People onshore paddled out to rescue the officer who stayed with the boat, but Potvin was lost from sight.

RCMP policy requires officers to wear a personal floatation device, such as a life-jacket, whenever they are in a boat or on a dock, Rogers said.

It is not known why Potvin was not wearing one while he was on the boat, he said.

The RCMP and federal safety officers are investigating the incident.

'Urgency, confusion, sadness'

Searchers along the Stewart River in Mayo, Yukon, on Wednesday. (Submitted by Samantha Anderson)Mayo, a village of about 250, is 325 kilometres north of Whitehorse in central Yukon.

Local residents, along with search and rescue personnel, have been helping RCMP with search efforts since Tuesday night.

"The street was completely lined with vehicles, with people just coming down to help and see what was happening," Samantha Anderson, a local journalism student, told CBC News.

There was "definitely a sense of urgency, confusion, sadness, all three of those things" in the community, Anderson said, adding that people are thinking of the young constable and his wife.

Rogers said a crisis intervention counsellor is providing support to Potvin's wife and family.