I'm new in the forum. I'm in a new buildings site team for some tankers. After sea trials we open one unit of the main engine to discover that the crankpin had 2 different kind of defects. one looks like watermark (imagine a map with 7 different countries that the borders have a depth of 0.1mm on the surface of the pin). It seems like oily water was left there and touched the pin while the engine was idle but we had nothing on the bearing which is strange.
The second one is a straight line that looks like pitting for 100mm but completely straight.
Can somebody help me identify exactly what it is and why it happened?
