In floor through hull drains, bilge pumps etc...

[McGillicuddy]

I couldn't find plastic or marleon long enough here so I went original with brass. My brass went in very smoothly, but if I were to do it again I would probably go bronze like Csick Nick did, or stainless. I really like how flush the flanges sit, but the brass is only .030" thick. Works and fits perfectly but it will fail again. I did crack an end but due to over-tightening and too much excess. Further annealing won't hurt. If you go this route do not exceed 1/8" - 3/16" the required length.

You will also want to make sure the wood block that supports the cockpit is perfectly sealed and all rot is filled with epoxy. My wood blocks were the source of water ingress and as the wood shrunk as it dried, the bond to the original tubes failed.

Do a "thru-hull scupper" search dating a few years and you'll find many scupper write-ups and fotos. Good luck.