Don’t a darn thing about ice and ships but how do ‘ice breaking ships’ do the chore?
They run up on the ice with the bow of the ship and the weight of it drives it downward and breaks the ice immediately underneath. After a while it creates a path by which a stranded ship can follow them out of danger and back to open water. If the ice is too thick the bow won’t be able to crack the ice and the ship will have to reverse thrust to get itself back off the ice sheet.