I broke a thru hull fitting off in the marina

[Pete7]

[QUOTE=Rorzech;2901721]

Originally Posted by a64pilot

I already had the thru hull installed but needed to pull the elbow that I had on it for temp when I was in the Bahamas, went under the boat and placed a thick piece of foam mat,

Do you think one of those old mouse pads could serve the purpose like the yoga mat did ?

We have a set of these. Not used in anger and I hope I don't need to, but quick and easy whilst you come up with a plan B or sit down after the drama and have a cup of tea.


Seabung - Breach Control Technology

[MikadoII]

Why is it that mention is only made of brass and bronze fittings. Is there a problem with 316 Stainless Steel?

[sanibel sailor]

Is it just me, but doesn't the broken thruhull look like it is plastic? A no-no in my book. I don't even care for them above waterline.

Stainless below water is generally another no-no, although tolerated for propshafts etc.

[fgd3]

Originally Posted by JBsurfin

Amazing.. Double layers Flex tape worked.. UNDER WATER as a seal.

Flex tape wasn't an option way back when I replaced that fitting.


Fabbian

[CarlF]

I agree with the comment that bungs are not useful in most leak situations. A bung only helps when 1) the hose has come off completely (not split) to provide a perfectly round hole AND 2) the seacock handle is frozen open. Neither should happen on a well maintained boat.

Instead of bungs, I carry several tubs of Stay-afloat which works with round holes and not-so-round holes.

https://www.youtube.com/watch?v=888wQhRcmjQ

[MikadoII]

Sanibel Sailor - Could you elaborate please. Why is SS 316 a No No?

[Pete7]

Originally Posted by MikadoII

Sanibel Sailor - Could you elaborate please. Why is SS 316 a No No?

It is susceptible to crevice corrosion in the absence of oxygen (underwater and covered in paint). Worse, you may not see it if its covered or difficult to inspect. You might ask why then we use S/S for prop shafts? well a 1" prop shaft has a lot more metal than a 1" through hull. The shaft is likely also protected with an anode.

Bronze is good but costly, so I am slowly replacing with Trudesign "plastic" fittings.

[Davo1404]

Originally Posted by Pete7

It is susceptible to crevice corrosion in the absence of oxygen (underwater and covered in paint). Worse, you may not see it if its covered or difficult to inspect. You might ask why then we use S/S for prop shafts? well a 1" prop shaft has a lot more metal than a 1" through hull. The shaft is likely also protected with an anode.

Bronze is good but costly, so I am slowly replacing with Trudesign "plastic" fittings.

True design make an excellent range of valves & fittings. They have USA Coast Guard & Lloyd's of London certification.

[MikadoII]

Thanks for your replies to my original query re SS through hull fittings. The mob Davo1404 mentions is Trudesign and their web site is https://www.trudesign.nz/marine/products. As they are just across the ditch in NZ they are almost Australian.

[Linesledaft]

Originally Posted by fgd3

Flex tape wasn't an option way back when I replaced that fitting.


Fabbian

Don’t bother trying it either. Hard to get it to stick to bottom paint. Same with toilet seal wax.

[rbk]

Originally Posted by a64pilot

You know while I can’t be sure, it looks as if there may be plumbing brass parts there, if so, be sure to not use brass, only bronze.
There is a form of brass that I believe is actually bronze, it may be called naval brass, but it’s also called by its metals make up, forget exactly what it’s called, but it has a bunch of fives in the name

Just plumbing brass won’t last long I’m salt water, it breaks

You may also want to look into a real seacock and not a ball valve on a thru hull, especially that small as that’s surely fragile.

Plus I believe there is no backing plate, just a hole in the hull?

Maine sail I’m sure has a write up on how to install a thru hull / seacock, I’ll look

Read this before you haul, and gather parts before you haul too of course
https://marinehowto.com/replacing-th...-and-seacocks/

Naval brass is better than say yellow brass but still not a suitable replacement for an underwater fitting.

[rbk]

Originally Posted by HopCar

This wouldn’t have happened if the thru-hull had been installed with a flanged seacock and not just a ball valve. I’ve heard of this happening twice before. Both times it was a 3/4” thru-hull that broke. I wouldn’t install any below the waterline thru-hulls without a real flanged seacock.

You show a Groco bronze ball valve. When used with their IBV flanges adapter, this is a superior setup to a flanged sea cock IMO. When the seacock fails you have to replace the entire fitting complete with haul-out (for most people). With the flanged adapter you just have to replace the valve (plug from exterior and replace). Biggest problem with using land based brass ball valves directly on a through hull fitting is the mismatched threads. You have NPS threads on your though hull (or you would have to re-thread when cut to length) and an NPT thread on the valve. They will never properly seal. The Groco flange adapter has NPS threads on the female portion and NPT on the male portion for the valve to thread onto. All ball valves are not created equally.

[HopCar]

Originally Posted by rbk

You show a Groco bronze ball valve. When used with their IBV flanges adapter, this is a superior setup to a flanged sea cock IMO. When the seacock fails you have to replace the entire fitting complete with haul-out (for most people). With the flanged adapter you just have to replace the valve (plug from exterior and replace). Biggest problem with using land based brass ball valves directly on a through hull fitting is the mismatched threads. You have NPS threads on your though hull (or you would have to re-thread when cut to length) and an NPT thread on the valve. They will never properly seal. The Groco flange adapter has NPS threads on the female portion and NPT on the male portion for the valve to thread onto. All ball valves are not created equally.

When you use a Groco Flanged Adapter you are making a flanged seacock. That’s fine. I, like you, have a problem with people who just screw a ball valve onto a thru-hull.

Some manufacturers of thru-hulls are making them with NPS threads from the head for a few inches and finishing the end with NPT thread. This solves the thread mismatch but still leaves you with a lot of unsupported thru-hull sticking up to get broken off.