Check out TruDesign they are a Fiber reinforced thru hull
. None of the problems of metal fittings.
I've replaced a few valves and fittings with their parts
now. It's really awesome stuff. Just make sure all of the parts
you buy have matching threads, unlike metal, they clearly mark it on their parts. (Most suppliers only bring in one thread type that I've seen).
Personally wont ever have metal thru hulls again.
The new metal, even Groco and other better brands, is not what it used to be.
I havent read every post so maybe this was explained, but the problem with the threads exposed like in the picture is that the weakest part in that whole setup is the valley of the thread. If the wall thickness of the thru hull
is 1/16", then the inside of the thread is only 1/32". Combine that long thread with the valve body and the pipe, you suddenly have a long lever hanging off of 1/32" of metal, that is being corroded by salt water