Removing Thru Hulls for resealing

[Fixit]

Groco not quite NPT threads on left NPS on the right

 

[Fixit]

NPT/NPS thread engagement on left. NPT to NPT thread engagement on the right

 

[Fixit]

You could have used a flanged adapter by Groco. It's straight thread on the inside (bottom) and NPT on the outside (top). Plus, because of the flange, it's a much more secure way to install seacocks/etc. The ideal way, and I don't know why Grady doesn't do this, is to first glass a block onto the hull, then screw down the flange adpater onto the thru-hull and then screw the flange to the block. Everything is MUCH more secure that way. Plenty of other manufacturers do this.

I, honestly, didn't even know you could change straight threads to NPT. Does that compromise anything by making the pipe/thread thinner?

the thread pitch and diameter are identical, but NPS lacks the 1.8 degree taper, so a big tap will make that change easily. Yes it does remove a tiny bit of material but doubling the thread engagement would make the connection stronger, plus now you have threads that self seal instead of relying on pipe dope, thread tape (or Grady white's silicone)

 

[DennisG01]

the thread pitch and diameter are identical, but NPS lacks the 1.8 degree taper, so a big tap will make that change easily. Yes it does remove a tiny bit of material but doubling the thread engagement would make the connection stronger, plus now you have threads that self seal instead of relying on pipe dope, thread tape (or Grady white's silicone)

Interesting. I never really thought to do that, before. I guess it doesn't take off as much material as I would have thought. Definitley - better thread engagement is important.

 

[Scottywotty]

I would like to resurrect this thread,
we replaced all of the thruhulls w/ stainless, however getting to all of the clamps, elbows, and hoses to get good tight connections is impossible. I was just wondering what anyone else may have done that we haven't thought of? This is a real issue for a boat that is in a slip, ultimately we just installed twist plugs into each one and called it good. but in reality its not. Kinda makes the whole "Live well" thing almost unusable.

Thanks for any advice,

 

[DennisG01]

I would like to resurrect this thread,
we replaced all of the thruhulls w/ stainless, however getting to all of the clamps, elbows, and hoses to get good tight connections is impossible. I was just wondering what anyone else may have done that we haven't thought of? This is a real issue for a boat that is in a slip, ultimately we just installed twist plugs into each one and called it good. but in reality its not. Kinda makes the whole "Live well" thing almost unusable.

Thanks for any advice,

Unless I'm missing something... you said you already replaced the thru-hulls so you must have been able to get to the clamps to remove them? Which means you should be able to get to them to tighten them - assuming you put the clamp head in the "best" (relative term, there!) position for accessibility. Otherwise, sometimes you need to cut an access hole and cover with a pie plate.

When you say "all" through hulls are SS. Not the ones below the waterline, I hope? If you trailer, it's not as big of a deal. But since you slip, that's not what you want. SS is not approved for below the waterline since it can corrode. Bronze is, by far, the best.

 

[glacierbaze]

If you can reach the clamp, but the tool is the problem, I like a palm ratchet.

https://www.amazon.com/PALM-RATCHET-DRIVE-mechanics-4137com/dp/B000T6DGVU/ref=asc_df_B000T6DGVU/?tag=hyprod-20&linkCode=df0&hvadid=241955516116&hvpos=&hvnetw=g&hvrand=2034840995355855389&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9009670&hvtargid=pla-570400903591&psc=1&mcid=cadb42cb83b73c2487afeb859ea41322&gclid=CjwKCAiAg9urBhB_EiwAgw88mYne78Ecb5PdVrJMNojZ81lbaWKn0M-RkItONF3MuaQ3NXBfjbVFqBoCX2gQAvD_BwE

 

[DennisG01]

If you can reach the clamp, but the tool is the problem, I like a palm ratchet.

And/or get creative with tools... different extensions, etc