Seacock Backing Blocks, Alternate Method No Through Bolts

[Richard19068]

Is there any concern about having to turn the through-hull into the flange when installing? I have heard that sealant should be applied to the underside of the mushroom through-hull and then pressed into the hull. Then without turning the mushroom, thread the valve onto the through-hull. So the sealant under the mushroom is not disturbed during installation. I have already made my backing plates per Maine Sails instruction, this thought about the sealant popped into my mind.

Here is Maine Sail's follow up on installing the thru hull. Apparently he doesn't have a problem with screwing the thru hull into the flange.

Installing A Seacock In A New Location - Marine How To

Choose the Location This photo is showing the spot for the new seacock & thru-hull as chosen from inside the vessel. Care should be taken when considering anew location for an additional seacock which includes, easy access, hose routing and seacock

marinehowto.com

"Goop The Thru-Hull
With the seacock or flanged adapter already installed and bedded to the backing plate, lather up the thru-hull fitting with a marine sealant of your choosing. For this installation I used Sikaflex 291.
The beveled mushroom head of the thru-hull fitting is what creates the water tight seal against the hull, and is the most important place to put sealant. Putting some sealant on the threads is only a secondary measure and adds some thread lubrication when tightening it down."

 

[Chipmunk88]

Thanks Richard!