Fire Main Maintenance

Senior Chief Engineman (SW) Joel Fletcher explains maintenance conducted aboard USS Underwood (FFG 36).

Right now we have a seawater-circulating pump that normally cools a diesel engine that is powered off the backside of the switchboard off the generator circuit breaker side. The pump is actually bad so we have the pump tagged out. You can run the diesel with emergency fire main back up aligned to it, which we are currently doing. Unfortunately, on the bad pump we had a mechanical seal let go and we also have a butterfly valve and a check valve with malfunctions.

So, as opposed to the fire main coming through a reducer at 32 plus or minus two PSI and going through the coolers and overboard, about 50% of the water is currently leaking by the two valves that have failed, leaking out of the mechanical seal, and going through the suction valve back to the ocean the opposite way of its original design.

What my guys are doing right now is shutting down the fire main to the entire space, tagging out the suction and the overboard valve. They’re removing the piping from the suction and the discharge side of the pump. They’re going to put blank flanges in on the pipes, and that’s going to keep the fire main from going back through the pump, which has a bad seal. It will be like that until the new pump gets here.

This is what’s called a voyage repair. You’ve gotta do what you gotta do to make things work.