How did the Danes fol the German dogs?

~How did the majority of Jews in Denmark escape to Sweden? The Jews were smuggled across the sea Baltic Sea (Kattegat) to Sweden in boats of local fishermen (like Henrik's). Some fishermen had built secret compartments in their boats to conceal people.These boats were often stopped in mid sea, and boarded by Nazi troops searching for Jews. One of their instruments was specially trained police dogs. To counter this, scientists in Sweden and Denmark created a mixture of dried rabbit's blood and cocaine, and laced handkerchiefs with the mixture. These were then distributed to the fishermen. When a dog smelled the rabbit's blood, it would sniff the handkerchief. Exposure to the cocaine would now temporarily destroy the dog's sense of smell. This is how the Rosens were able to escape. Tomorrow we find out other things that they have not told Annemarie. The picture below is an actual boat used by the Danish Resistance to help Jews escape across the Baltic Sea.