correct installation of skin fitting & seacock

[tgalea]

Hi All,

This winter i'm planning on replacing a sea cock or two and from previous experience would like your opinion regarding this problem i encounter.

Normally, i first install the skin fitting on sikaflex and tighten the nut from the inside. Problem is, as soon as i start tightening the sea cock i eventually end up un-tightening the skin fitting and it normally turns out to be a nightmare.

How should this be done ?

Thanks & Regards
Tyrone

 

[sarabande]

Is the sea cockatoo one of the speaking ones ?

 

[Strathglass]

The skin fitting will have a couple of nibs inside it.

You find the correct size of chisel which will fit inside and stop it rotating. Then you get a friend to hold the chisel outside the hull and stop the skin fitting from rotating while you fit the sea cock.
I have two to fit but have put it off till I get someone to help me.

Iain

 

[sailorman]

not all have the nibs.
you may have to use 2 locking rings ( nuts ) to act as lock-nuts, hold with spanner or water pump grips from the inside of the boat

 

[alec]

S'right.

Mole grips ! The singlehander's best mate.

Keep on turnin' till the buggers grab...............

 

[oldsaltoz]

Also check the inside of the outer fitting, some have nibs that locate into small slots cut in the edge of the hole.

I use an old tyre lever with a large shifter to stop turning.

Avagoodweekend

 

[cliff]

The engine cooling through hull fitting on mine has two flanged nuts on the fitting - one to tighten the fitting into the hull (flange down) and the other to tighten the valve to the fitting (flange up).

Fit the through hull and allow the sika to "go off" before tightening the first flanged nut. Fit the second flanged nut flange up, apply PTFE or what ever sealant you prefer to the threads where the valve will be fitted then HAND tighten the valve onto the through hull. Gently nip up and adjust the orientation of the valve then bring the second flanged nut up against the botton of the valve and holding the valve tighten the flanged nut against the bottom of the valve. The through hull should not move at all. This method also maked removal easy as once the second flanged nut is loosened the valve should unscrew from the through hull quite easily.
--------------------

"Artificial intelligence is no match for natural stupidity"
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[FrankJB]

[ QUOTE ]
apply PTFE or what ever sealant you prefer

[/ QUOTE ]

I had a bad experience with PTFE tape last season. I had fitted a new skin fitting and seacock the winter before using PTFE tape for the seacock joint. It worked fine for that season but after the following winter lay-up it began to seep on relaunching (costing me a vast sum of money to have it hoisted out again for 20 minute to fix it!).
When I dismantled it I discovered that the thread was such a good fit it had removed almost every trace of the PTFE tape!
I would use Hylomar or Hermatite with the benefit of hindsight.