Thru-hull evaluation

[Suijin]

Discuss:

[deblen]

I'm guessing some here:

That appears to be a bronze mushroom head type thru hull / skin fitting in good condition,but-which are only available in National Pipe Straight thread in N.A.& is intended to screw into a proper NPS threaded seacock.

Instead,it has been mounted to the hull by using a bronze flange nut tightened against the hull shim.

An earth bonding wire has been clamped to it by a SS gear clamp-OK,because that is the only way of fastening a wire to that type of fitting AFAIK & if you believe in the necessity of bonding individual fittings.
AFAIK-there is no harm nor benefit in doing so-My Opinion.

Then,a bronze adapter with I assume female National Pipe taper thread has been screwed about 3 threads onto the NPS threads of the mushroom.
This is the weak point-only 3 threads holding out the ocean.

Then a black plastic?? or other material item has been screwed onto the top male NPT threads of the aforementioned bronze adapter. Hopefully,the black item is NPT thread also.

No shut off valve(seacock) visible.

This is a common way to install thru hulls/skin fittings.

Please read Maine Sail's excellent analysis of this type of installation

Seacock & Thru-Hull Primer/Pre Information Photo Gallery by Compass Marine How To at pbase.com

Len

[deblen]

Maine Sail's opinion re mixing Straight (parallel) thread with Tapered thread, regardless of whether American National Pipe or British Standard.

[UNCIVILIZED]

In addition to what's been said, the backing block is moving, as is the nut. So at a minimum it bears disassembling for inspection & repair. Which, why not make things right since you need to pull it anyway.

[Suijin]

Originally Posted by UNCIVILIZED

In addition to what's been said, the backing block is moving, as is the nut. So at a minimum it bears disassembling for inspection & repair. Which, why not make things right since you need to pull it anyway.

This is what I was thinking and wanted some input. it's the last remaining original seacock on the boat, 32 years old. I thought they were all newer but overlooked this one.

The green also concerned me although it just appears to be surface copper chlorides. Someone at the yard said that forms from exposure to salt water, which was alarming.

There is a shut-off, just no visible in the picture.

[rbk]

All my originals were better installs and better shape but they still got pulled for replacement. I wouldn’t question replacing this especially when it’s just one.

[deblen]

Originally Posted by Suijin

This is what I was thinking and wanted some input. it's the last remaining original seacock on the boat, 32 years old. I thought they were all newer but overlooked this one.

The green also concerned me although it just appears to be surface copper chlorides. Someone at the yard said that forms from exposure to salt water, which was alarming.

There is a shut-off, just no visible in the picture.

If those fittings have been in service 32 yrs I am willing to bet they are high quality marine bronze.
The green is verdigris-common on any copper bearing metal in a salt environment. It is basically harmless to good bronze.

When you do remove these fittings,check for any pinkish tinting as explained by Maine Sail . That is the test to determine "rotten" underwater yellow metals.

[HopCar]

I don't know what I'm looking at but it looks bad. Replace it using Maine Sail's instructions.
Since he wrote those instructions, Groco started making backing blocks that are a little better than he describes making. The Groco backing blocks have threaded inserts that eliminate the need of bolting through the hull.