The risk was high and brute force essential:
In the olden days, skippers used axes and later even dynamite to open up shipping lanes or entire ports covered by ice. Real success was rare. Later, technological progress made it possible to build ships able to brave even strong ice sheets.
Such vessels are characterized by stable steel hulls and ultra-powerful engines. Today, icebreakers keep shipping lanes free. And fully laden ice-going cargo vessels can deal with ice sheets up to 5 feet thick. Without needing help.