Originally Posted by Boobaychap
thinking it may be the drain plug.
How can I test to identify the source?
Also, what's the procedure to reseal the plug?
Hopefully it's out of the water -
any chance the threads are damaged / cross-threaded and not sealing?
Testing could be tricky - I would try - (dreaming this up as we go) - a plunger that fits in this zone.
A low profile test plug /teflon tape on threads/ so plunger can slid over it when bilge filled with water an inch or so.
Compress plunger & release a few times to fill plunger as much as possible with water - then apply constant pressure - filled plunger of water over plug.
By yourself - may have to set up video to see drain plug up close - review to see trace of leak.
If not leaking around flange of drain - thats a good sign threads are maybe the cause.
If plunger is a no go - may have to fill it more to create enough pressure to see leak.
Couple drops of dish soap makes water wetter testing.
Good luck - image would help.