I joined my first ship at age 9. My Father was the Engineer and it was a an oil fired Admiralty 3 drum boiler driving a triple expansion engine. It was the best toy a boy could ever have.
I wasn't allowed to go to sea without my Father until I was 13. (This was because my Mother couldn't swim and therefore I wasn't allowed) So at 02:00 on my thirteenth birthday I was shoving of in a 10 metre cray boat. That was about the best dose of sea sickness that I have had (So Far). I think it was because of all the time we spent hove to, pulling cray pots with the boat rolling all over the place. Either that or the bait that we were using was the culprit. It was full matured, blue vein cow hocks complete with maggots and other crawly critters.
At 17 I graduated to destroyers, 4 x Foster-Wheeler "D" type boilers at 1275 PSI and 2 x GE steam tubine and gear box.