So I used the Marelon from CD, they were kinda pricey. The flange is problematic because you have to be careful where you cut the hole in the bottom corners of the cockpit. The flange keeps the level of the tube about a 1/2 inch above the level of the cockpit deck. If you use fiberglass tube, the brass flanged tubes, or just filler resin and glass like Gene did its possible to get the bottom of the tube flush with the deck to drain all the water out. Then again, that is not the purpose of these scuppers; they are there if the cockpit gets flooded rapidly by a wave or the main foreword scuppers are clogged... so I don't think having residual water on the cockpit sole will be an issue.