Could have been very nasty.

[David2452]

I was replacing the whole assembly anyway as the valve was a bit stiff and there was some corrosion/erosion evident but I wasn't prepared for what happened. Undid the hose clips and warmed the hose with a heat gun and twisted without much force and the skin fitting just snapped, it was extensively corroded internally. This was the dump valve for the holding tank and the raw water intake looks OK but it's having a new Marelon valve next weekend too so at least the next owner will have no such worries. We've had the boat from new in 2007 and she's had a galvanic isolator from year two. Could have been nasty if it could have happened at sea when I tried to operate the stiff valve even.

 

[Poecheng]

Its the waste outlet seacock again.
My boat surveyed July 2013 and only the heads/holding tank outlet was corroded. I have read other threads where this is a common theme - the heads outlet is u/s. My surveyor said that this was common - something in the "products".

If you only check/change one skin fitting, make sure it is the heads outlet. Not only is this skinfitting the one that seems to "go" but it is generally the biggest hole !
As David has done, I changed it for Marelon

 

[vyv_cox]

Any photos? Always looking for illustrative stuff for the website and for my talks.

 

[David2452]

Any photos? Always looking for illustrative stuff for the website and for my talks.

No Vyv, but I know a man who does, I'm sure he will post them later, obviously you will need his permission to use them but I don't think that will be an issue.

 

[pks1702]

Photos as requested.

Please use as fit, PM me a mail address if you want the originals.

Poor shot of the not yet finished Marelon installation.

 

[vyv_cox]

Excellent, thanks very much. Vyv.