Water Line

[willy]

Tin I've seen them before and asked guys about them but have been told they are for a certain type of deck drain hole. My V has scupper holes that are in the seam between transom wall and floor and these will not fit.
We need an in-line type of valve for the hose area or an external valve the attaches to the outside of the hull where the thru hull is.
I was on a bigger boat this past summer and looked down at the thru hull as it bobbed up and down on the water and it had a flap arrangement on it that let water out when it had positive pressure from inside boat like moving forward or when boat lifted thru hull up out of water while bobbing.
Thats what I want to install on Old School