A Canadian frigate departed Halifax Tuesday to replace a sister ship that is part of a NATO maritime force aiming to reassure eastern European allies that are worried about the crisis in Ukraine.

HMCS Fredericton will take over from HMCS Toronto which is in the Mediterranean Sea.

Toronto has been in the area since August and Fredericton is expected to deploy for a similar six-month period.

In about a week to ten days, Fredericton and Toronto will do, what the navy calls, a chop. They will pass one another and exchange the mission, which is set to happen in Spain.

“Toronto needs you, they been there a long time and they want to come home and have their Christmas,” says Rear Admiral John Newton to the departing sailors.

Defence Minister Rob Nicholson said the ship is being dispatched as part of a broader Canadian message to Russian President Vladimir Putin that Ottawa disapproves of his government's involvement in the Ukraine.

“Whether it be with the deployment of this ship, with the deployment of our air force and the soldiers we have had on the ground we are absolutely committed to sending out the message that what Putin has done is unacceptable,'' the minister said after the departure ceremonies.

“We remain steadfast in our commitment to supporting Ukraine and our allies in the face of the Putin regime’s aggression and will remain so.”

Four CF-18s were deployed last fall as part of NATO's mission in response to Russia's annexation of Crimea and support of pro-Moscow backed rebels in eastern Ukraine.

Nicholson has recently said Canada is searching for bilateral ways to expand military training with the embattled country. Canada has already donated quantities of non-lethal military equipment to the government in Kyiv.

In August, the Defence Department delivered helmets, protective eyewear, first-aid kits, tents and sleeping bags. Last month, the Canadian Forces began shipping more gear, including tactical communication systems, explosive ordinance disposal equipment, tactical medical kits, night vision goggles and winter clothing.

HMCS Fredericton is the first of the modernized frigates to deploy on a NATO mission. It has recently been upgraded with a new combat management system, refurbished radar systems, upgraded communications and a more recent generation of missiles, to better track and target aircraft

“There's been considerable effort put into the radar, infrared and sensor,” says Newton. “There's a very quick turnover from tracking to locking on with missile control and gun control radars.”

The Royal Canadian Navy hasn't indicated yet how ships on overseas missions will be refueled and resupplied without the use of the two Canadian supply ships - which are both out of service.

Nicholson said Canada is working with its allies, but said no firm decision has been taken yet on what to do about the supply ship issue.

The ship departed with a crew of about 250 people and a CH-124 Sea King helicopter and air attachment on board.

Family and friends were bundled against the cold, minus 21 with the wind chill, as they stood at the dockyard in Halifax to say goodbye to their loved ones.

Nicole Lewis says the departure of her husband, Lt. Joesph Lewis, is toughest on the children.

“Explaining to her why daddy’s not coming home,” says Lewis.

Jessica Bond’s fiancé is on the Fredericton. She says she is grateful for the support of family and friends while he is at sea.

“I have family not too far away, so I think we'll be good, our neighbors are pretty good at helping out,” says Bond.

Major Rebecca Wilkenson has been through it all before, but from the other side.

“I deployed about two and a half years ago and left him behind and now it's his turn to go,” says Wilkenson. “It's fun to go because you know you're going on a mission and being left behind is a little harder in my opinion.”

There's no set time for Fredericton's return, it is expected to be about a six month mission, but could stretch to seven or eight months.

With files from CTV Atlantic's RIck Grant and The Canadian Press