Help Understanding how to measure thru hull length

[zboss]

Hi,

I am trying to understand the instructions on Mainesails website:

"1- With the thru-hull bottomed out into the flange measure from the outside of the hull to the mating side of the mushroom-head and add 1/4 of an inch."

On the following page:

Replacing Thru-Hulls and Seacocks Photo Gallery by Compass Marine at pbase.com

I'm being dense I am sure... but I just don't understand these directions.

Thanks,

z

[dugout]

I will take a swing at this.
Assuming your seacock is in the hull just thread the new thru-hull thru the bottom into the seacock. It will bottom out at some point, stop turning, run-out of room in the seacock. Say, for example, there is now 1" between the hull and mushroom of the thru-hull at that point. He is saying take it out and cut 1-1/4" off the thru-hull. This way it will thread into the seacock and the mushroom head will snug up to the hull with 1/4" more room to spare in the female threads of the seacock before the thru-hull male threads run out of room in the seacock female threaded area.
I hope this helps!

[zboss]

ok... that makes sense! Thanks!