drain pipe replacement

[dbbd]

I need to replace the knee pipe above the black water drain seackock. (#2 in the picture).

Any idea what diameter is that pipe? what kind of threads?

This is a Jeanneau SO 45.



Thanks,
Dan

[rxc]

On my boat those elbows were originally 2-inch BSPP (not tapered) threads. Since I changed them and the valves, they are now 2 inch NPS (Straight) threads. You have to use a sealant with non-tapered threads. 4200 works well.