Dear Vibration people
Am facing an issue with four of our fire pumps driven by engine with rectangle gearbox and 10-12 meters length suction column from the sea. All the four pumps having this oscillating problem and due to this the top side flanges getting damaged and the pump is hitting the walls of drum also the cathodic protection anodes at the bottom. Bump test conducted but couldn't find anything.
Please suggest me to reduce the oscillation and if you have faced any problems before like this please share