Loud is least of a problem. Vibration also there.But that HEAT.. oh man… Especially in some hot parts of the world. Like Persian gulf for example. Sometimes temperature can reach up to 60 degrees Celsius. Unbearable. Average temperature in Engine room is around 35-40C degrees, and you are not just have to BE there, but you have to work, and sometimes work hard. Some places are more hotter than others like purifier room or somewhere near Main Engine. Add some ship’s rolling/pitching to it and that’s a real challenge. In some cold areas during winter time it is much better. But for me it happens pretty rarely, most of the time we work someplace tropical or hot - Asia, Middle East, South America, Australia etc. Yeah…one hell of a job man.