Skin fitting fitting!

[nigelmercier]

One of my skin fittings has lost half of the rubber seal on the outside, see picture.

I have not tacked this job before, any advice on re-fitting it?

In particular: type of rubber seal(s), use of sealant, tightening torque, and how to stop it rotating.

 

[vyv_cox]

All skin fittings like this on my various boats have been fitted using sealant only and I have never seen one that had a rubber gasket. No reason against having one but it doesn't seem necessary. I normally use Sikaflex 291 for both under or above water sealing but polysulphide sealants are supposedly better underwater.

Tightening torque is a difficult one as you are unlikely to be able to get a torque wrench onto the nut due to the length of the fitting. Ideally you would apply the sealant, tighten the nut until sealant is extruded all around the fitting, wait half an hour and then tighten quite tightly, e.g. using a 12" spanner pretty much as tight as you can get it.

If you look into the bore of your fitting in the photograph you will see a lump at the 4 o'clock position. This is a key to prevent rotation. Put something in the bore alongside it, a large square-shank screwdriver held with an adjustable spanner works well, and tighten against that.

 

[Tranona]

That type of rubber seal seems to be peculiar to Bavaria. Although breaking up on the outside, the seal through the hull skin is probably still sound.

As Vyv says, nothing magic about taking out and re-sealing - I would use polysulphide, but more through 30 years habit than anything. Not a nice job as access is a bit awkward, particularly if you are regular size. Definitely a job for aspirant jockeys!

 

[auditdata]

See this post and lots of help from PBO forum
http://www.ybw.com/forums/showthread.php?t=254387
Also my progress to date on replacing one of my skin fittings.
http://www.sephina.org/index.php?option=com_content&view=section&layout=blog&id=6&Itemid=54
Proved not to be as easy as I thought but got there in the end. If you click on the photo on the right of the web page under seacock thruhull you will see my progress.
Clive

 

[ghostlymoron]

Is it leaking? If not - do nothing. You could cut off the rest of the sealing rubber to make it look tidy. It's what's under the flange that's important, not the bit outside. If it is leaking, Vyv's advice is good.