One of the ways that the British Navy became so powerful during the mid to late 1700's was through the use of merchant ships in times of war. The ships were often already fitted with guns for their own protection, so it was a logical jump to outfit them just a bit more and use them for war. How was this different than privateering? Also, what was the average merchant's response to this? Loss of profits?
Thanks!
I'm not sure your chronology is quite correct there; the English/British fleet had been comprised of large numbers of merchant vessels since time immemorial (actually, that's a joke -- it was comprised of both king's ships and privately owned ships dating back to the days of Alfred the Great, before time immemorial). The fleet that fought the Armada, for example, was comprised not only of queen's ships or those taken up by her command, but also by private ships brought into service by their owners or Elizabeth's admirals.
By the 1700s, merchant ships were not usually part of the battle line, but they could be requisitioned for transport service or contracted for shipping materials -- maybe that's what your source means? The ability of the British to sustain themselves overseas was a major factor in their expansion in their first and second imperial periods, and having a merchant fleet was a major part of that.
How was this different than privateering?
Privateering is a legal status, where a private individual is granted a letter of marque or a letter of reprisal to attack designated enemies under the permission of the law of the issuing country. It's sometimes called "legalized piracy" because it does make legal acts of war carried out by private individuals. But merchant ships, whether under contract/convoy by navies or not, could defend themselves from attackers without falling afoul of rules of law; aggressive action is what the letters of marque legalize and regularize.