Since there are different types of engines used in both the marine and other industries you must be target specific.There are Engine manufacturers like Man B&W and sulzer who specialize in constructing large two stroke diesl engines for ship propulsion. Small engines may be used for generation of electrical power supply, they are generally four stroke engines and are termed as diesl generators. The types may vary from yanmar, dihatsu, catterpillar etc. you can post these names on the website search engine and you can get some info. But if you which to purse a detailed study I woul suggest that you take some basic books and get your basics right and following that you could refer the engine maker manuals both operation and construction.
But it is difficult to get them and if you get an opportunity to vist a ship do it , dont miss out on it.
cheers,
bye and Best of Luck,
Aditya Srinivasan