In Medieval days up till the early 1800's there were no engines and no Snipes. Along about 1812 the Navy obtained their first paddle wheel steamer named the USS Fulton. To run the boiler and engine, men of steam were also acquired. They were not sailors but engineers from early land based steam engines.
From the beginning the sailors did not like or appreciate these landsmen and their foul smoky plants. They were treated with contempt and pretty much given the short end of the stick.
In spite of all this the steam engine prevailed. There were still two crews however. The Engineers and the Deck crew. Soon an Engineer Officer was appointed to each ship. He was the Engineer master and all the Engineers reported to him. The Deck sailors reported to the ships master. Curiously, the two masters were on equal footing and neither was over the other. The Deck Master though was in the best position. He controlled the quarters and rations. The Engineers were still at the mercy of the deck gang. By the height of the civil war, as steam was taking over and sails were disappearing the old Admirals that controlled the Navy were in a quandary what to do about the situation.
They accomplished a couple of things. First, they managed to make the senior Master a Captain. As Captain he was in overall command of the ship and the Engineering officer reported to him. Beings as how there were occasions that the Engineer master outranked the ships master something had to be done to keep the Engineer from becoming "Captain". To solve this problem they developed two separate Officer branches. Staff and Line. Only Line Officers could succeed to command. Staff Officers would always be subservient to Line Officers at sea. Staff Officers consisted of Surgeons, Supply and yes, Engineering officers. To this day that is still true. The second change was to make all engineers's Navy men, however they were also made junior to all deck sailors. A petty officer machinist was junior to a deck seaman third. All this went to make the life of the engineers even more miserable. They could now be flogged and harassed at will by the Deck crew.
Along about this time came an Engineer Officer by the name of John Snipes. I cannot find the name of the ship he first appeared on, but he was a different cut from the others. He demanded sleeping accommodations, and food equal to the Deck gang. He also declared that there would be no more harassment for his gang. When the ships Captain laughed at him, Snipes simply had his men put out the fires in the boiler. To make a long story short, Snipes brought about the changes in the system. In time these changes extended to the entire Naval fleet. The Engineers became strictly "hands off" for the Deck gang. They became known as Snipe's men and over the years as just Snipes.
(btw: The IC rating are now part of engineering thus snipes too, but the below picture is missing the rating insigna because it's so new)