Raw water strainer thread failure

[BobHorn]

The attached photo shows some of the threads breaking off on the body of the A/C raw water strainer. Some parts are so brittle you can break them off with your fingers. Any thoughts a to the cause? A/C was installed 6 - 7 years ago and I assume the strainer was put in at that time.
Since it's below the water line, having the threads fail could be serious.

[Bellinghamster]

Some plastics are incompatible with some oils... it looks to me like someone may have put lube on the threads that caused the plastic to craze and fracture.

For below-the-waterline filters I'd recommend changing to a bronze body filter of reputable brand (Groco or similar). I definitely would retire that one ASAP!

[BobHorn]

The lube thing is a possibility, there have been some strange things done to this boat. That strainer is definitely not going back in. The two A/C units are the only ones with the plastic strainers. Space wise it might be difficult to put in one of the bronze strainers. Putting in a Shurflo for the time being.