@anon331721-- My dad told me that "blow smoke" originates from WWI, not from war at sea but rather on land.
Apparently, the allies in WWI tried different tactics to trick the Germans to give away where they were shooting from. They would make human dummies, place them in the trenches and wait for the Germans to see them and shoot, so they could shoot back.
After a few days, the enemy figured out what was going on and wouldn't shoot at the dummies. So the Allies fooled them one more time by blowing smoke from the dummies' mouths with a tube. And of course, it worked!
I have no idea if this has any truth to it but it sounds plausible to me.