Don.
Before the automation of the engineroom the engineers used hands, eyes, ears and noses to detect irregularities of the engines. Water in the lubeoil as well as fuel might enter the system in many ways. The most common was the leaking of the main hull exhaustvalves. Leaking pipes in coolers/heaters and some times in watercooled exhaustvalves in the cylinder cover. Each leakage gave different indications. It would be impossible to list up all the different aspects, that`s why you got to have experienced engineers. F.inst. waterleakage in the exhaustvalve casing would be seen on the colour and temperature of the exhaustgas, water in the lubeoil could be detected by condensation droplets in the crankcase. When the oil settled in the systemtanks the hand pump could be used to have a visual check by looking on the discharge in the funnel.
You always would run the engines on air ( no fuel injection) prior to starting. Emulsification happens over some time, we checked the oil visually and when we saw sign of emulsification, the oil turned gray, became like mayonaise, we had to drain it from the system. This did not happen all the time, I experience this once in three years.
Piston rings can have a water leakage even if a compression test is OK. As piston rings have a split (gap) water can pass when the engine is not in operation. The main tigthening of the pistonrings do not come from the initial spring effect but from combustionpressure and compressionpressure leaking into the pistonring groves at the back side of the compressionrings, forcing the pistonring towards the cylinder wall.
Whenever the engine would be turned by air or manually you would start the aux.lubeoilpump to protect the bearings.
The diesel engineers have many means to detect watercontamiation of the lubeoil, experience is the key and not everything can be put down on paper.
Tore
