Sailors plucked the animal to safety after it got trapped on ice on Poland's Vistula river and drifted for more than 70 miles.
Rescuer Adam Buczynski said: 'He didn't even squeal. There was just fear in his big eyes.'
Trapped at sea: Baltic perched on an ice flow after drifting for four days before being rescued.
It’s thought Baltic’s problems began when he got trapped on ice on the Vistula River near Torun on Friday.
A day later he was spotted in Grudziadz, 40 miles upstream, where fireman tried to reach the German shepherd-type mongrel.
But thick ice made it too risky to launch a rescue craft despite Baltic floating just a few yards from the river bank.
Another bid to save the stranded mutt was made at Kwidzyn, 22 miles further on towards Poland’s coast.
After sightings dried up it was assumed the dog had perished.
But incredibly Baltic had travelled a further 50 miles to the river mouth before heading out to the ocean where finally his luck turned when scientists on a research boat spotted something odd moving amid the broken ice.
Natalia Drgas, of the Institute of Meteorology and Water Management, said: 'One of the sailors thought they had seen another seal but then he noticed it had legs, ears and a tail.'
However the men on board the Baltica soon found saving the stranded dog was by no means plain sailing.
First they tried to catch the dog in a net on a pole but when that failed they had to drop a pontoon with crewmen.
Seaman Adam Buczynski said: 'We tried to sail as close as possible but as we approached the boat pushed the ice and the dog was sliding off.
'The dog didn’t even yelp but you could see the fear in his eyes.'
With darkness falling and time running out Baltic was finally hauled on board in sub zero temperatures late on Monday.
Captain Jan Jachim said if his ship had passed that way a few moments later the dog would never have been spotted amid the gloom.
He said: 'We were just at the right place at the right time.'
And he added that few boats chart those waters at that time of year.
'Baltic was drifting with the current further and further out to the open sea. He would have gone further if we hadn’t seen him.'
But Captain Jachim may not have seen the last of the Baltic, the salty seadog. If no-one claims him, the lucky hound will be adopted as the ship's mascot.