Releasing a 'through-hull'

oldbilbo

oldbilbo

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I have a deeper understanding of why the previous owner of this @@***## boat fell into a deep black despair....

One of the bronze through-hulls is most reluctant to part from its BIG bronze Hattersley shut-off cock. Peeps on here told me about 'step wrenches' and how these, inserted into the through-hull, engage with lugs formed on the inside of the tube. With one turning the shut-off cock from the inside, while a helpful SWMBO holds the 'step wrench' and its skewered through-hull from rotating on the outside, the two components should unscrew and part.

Except that this through-hull doesn't have any internal lugs....

The others do, but they're not the problem. This one is not watertight. It needs to come off.

Now, even if I could find a supplier of 'step wrenches', which I cannot, I'm stumped as to how to hold the blessed through-hull from rotating while its mate is unscrewed. Or from disconnecting the thing 'permanently' so I can go source another......

I earnestly and once again seek the guidance of experienced 'fettlers of through hulls'.

Eyethengque. :cool:
 
Is it actually turning? An alternative to internal lugs is a web between the barrel and the flange, that fits into a slot filed in the hull at the edge of the hole. This then stops the whole issue turning, without needing swmbo on the wrench, and as an added bonus avoids the detritus-catcher in the bore of the pipe which a pair of lugs represent especially on a small fitting. I prefer the web version.

Alternatively, take a hacksaw, cold chisel, angle grinder, and/or holesaw, cut the thing off, and replace it.

Pete
 
I think it's time for the angle grinder! Remove the inner radius of the outside flange of the through-hull, until the flange drops off. Knock the rest of it through into the hull. Take the bits home and dismantle at your leisure.

Incidentally, you can make a "step wrench" by grinding 2 slots in a suitably sized socket. I did this when I last fitted a through-hull, and was able to wedge the socket handle against a step-ladder, thus doing the whole job without the need for my glamorous assistant.
 
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When Fox's replaced my holding tank valve and thru' hull last month Ralph told me they always take an angle grinder to the thru hull; takes a few minutes in expert hands and saves wrestling with frozen freds on the valve/tail inside. They can be lifted away, the hose removed, and the valve etc wanged in your biggest vice for fettling--unless you are replacing all with new.
 
When I bought my boat I thought I'd replace them all as a 'belt and braces'. Spent a day trying get hold of a suitable tool and another trying to get them out (plenty of knuckle rash too). Then went and bought an angle grinder and they were all off within an hour. The few £ for new thru hulls seemed like a bargain and I wish I'd not wasted so much time before resorting to the angle grinder.
 
Just had same problem last month - small angle grinder used very carefully from outside had it off in three minutes.
 
How about an Internal Pipe Wrench? Like this, but probably bigger:

http://www.amazon.co.uk/exec/obidos/ASIN/B000AO1IOI/dolcetto-21

internalwrench.jpg
 
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Give me an angle grinder any time - We changed our through fitting last month and encountered no problems at all in doing so - We used Sealift in Haslar for the lift-out and was back in the water in an hour and half which saved us a lot of money compared to a conventional haul out. Also cleaned the antifoul - props and trim tabs as well as washing down the sides of the boat :D
 
Yep same, had to grind/cut all thru-hulls out on the last boat. Its easiest way, unless they incumbents are relatively new.
 
Angle grinder for me too. Use a cutting disc in it. I worked from inside the boat, not always possible I know, I cut the seacock off the skin fitting then two cuts in the flange nut, with a bit of pressure the skin fitting then pushed out of the hull.
 
Surely inside the hull there is enough exposed thru hull thread to get a pair of Stilsons on? And a second pair on the body of the seacock.
Bad old bodger owners curse their boats, good owners make em purr, think of it as a cathartic experience!
 
Blueboatman said:
Surely inside the hull there is enough exposed thru hull thread to get a pair of Stilsons on? And a second pair on the body of the seacock.
Click to expand...

Nope. Tried that.... and failed. I suspect there were lugs inside the through-hull fitting at one time, for I can just feel 'something'. The one on the opposite side still has its lugs.

I think its time for surgery, replacement, and move on.
 
The Stilsons aren't gripping or there is insufficient thread/access/leverage turning room ?

Be careful of angle grinder internally in case it grabs and bursts ( at the risk of patronisingly obvious, sorry),

Grind a slot across the face ( extrrnal flange) of the thru hull , apply tire lever with mole grips (2) on each end for leverage, and some sort of wrench internally on the seacock..

I suppose you could sttack it too with judicious blowtorch heat on the conjoined assembly..

It will ' go' cos it has to!

Maybe you need mark one Ruffytuffy ' dont know mevown strength' agricultural mate on one side n you on t' other?
 
It'll be seen that there's no room in there for an angle grinder - with the diesel supply pipe alongside - and would be asking for a severe accident. Stilsons couldn't move it with the awkward and limited force I could apply. The whole thing turns, so the fitting would leak, so it all has to come off and be 'fettled' or replaced with something better.


IMG_3438.jpg



My sincere thanks to the several who made useful recommendations. I was a bit leery of using the angle grinder due to awkward positioning, so tried a hacksaw, then a vibro multitool, with next to no result. The angle grinder with thin cutting disc did the business - or most of it. The final blows were struck by a 4lb lump hammer onto a stonemason's toothed scutch chisel.


IMG_3439.jpg



Another result for the assembled knowhow of 'here'.... :D

Eyethengcue.....
 
there was I, cheerfully assembling the scraped out propellant of a few rounds of ammunition, a 7ft iron fencing bar, air-powered percussive Kango hammer head, a few inches of det cord, and several cans of WD40, when you post pictures of a successful extraction.

Where's the fun in something simple like a disc grinder ? ;)


One down; how many to go ?
 
I'm not sure .... but that looks like a bronze seacock. It might still be good.

I've used Marlon? fibre reinforced plastic through hulls and seacocks with good success .... and they haven't seized yet.
 
On the basis that if the first ( S ) seacock hds become close to impossible to operate, I cannot readily remove it for strip-down and servicing and it therefore must be replaced with something that works as asked, I have reluctantly also removed the second ( P ) one.... reasoning that it is only a matter of time before that, too, misbehaves.

I'm glad I did. The reasoning was right.

Mounting the whole assembly on my Triton Superjaws clamp-vice and using 20" Stilsons, it took me over two hours to persuade the thing to disassemble. That's a tribute to whatever was used to seal the threads - Sikaflex291, most likely - but I'm glad I didn't require to wriggle into the innards of the 'engine room' to do it, for I'd still be there....
 
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