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Removal of Through Hull Fittings


Grinna

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What's the recommended method for removal of through hull fittings?

 

Obviously step #1 is removing the boat from the water, but is through hull fitting removal a boat builder job or something that's relatively easy to do?

 

Will be going with a larger fitting to replace the current unit in order to flow more water.

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Think it makes a difference whether they are bronze or plastic and whether you are taking them out of timber, glass or cored construction.

 

I would call it owner-doable as long as you don't end up with such a mess that the project ends up taking longer/costs more. Talking splintering them out the outside of your hull here.

 

I pulled a couple of plastic transducers out of the 88 when we upgraded the instruments, if that has any parallel with what you have lined up. My first suggestion would be put your hammer well out of reach for the duration of the job. :thumbup: The collars on the inside were pretty easy to get off but then it was a matter of separating the sealant. I wasn't trying to save the fittings and used a combination of snap-off knife with long blade, multi-grips to twist and a hacksaw blade. Not a long job but hard to resist the urge to smash them out - the sealant was holding well enough that it would have done damage on the way. :twisted:

 

Then knife blade again and a sand to clean away the leftover sealant. I had a boatbuilder doing the install of the new ones so can't tell you what happened after then.

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They'll be bronze on your boat I'd expect. They're either going to be easy to undo or not. I usually end up cutting the nut on the inside and pushing the body out. Easy as.

 

To bore the bigger hole accurately a simple way is to use a holesaw. Depending on the hull material either temporarily glue in or knock in a wooden bush or plug to give you new timber to get the centre drill started.. stops the holesaw from chattering out a football shape. :lol:

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Second cutting thr nut off - I woud recomment trying to unscrew the thry hull out before pushing it through - took some time to un-screw it from but was worth it as no damage to surrounding timber.

 

Have seen a guy drill a couple of small holes into the outside flange of the thru hule and use a home made tool with pins that fitted the drilled holes with a bit of encouragement - gave good lever for turning.

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go to the outside of the boat

get a hole saw the same size as the through hull thread

find the centre of the skin fitting

drill the hole thing out in one

 

Did it on WT that way. Took about 3 mins. Sweet as.

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I've seen a method described very much like that WT. Whack a softwood plug in the skin fitting from the outside, cut the plug off flush, mark the centre and use a holesaw the same size as the threaded portion of the skin fitting or just a touch smaller and the whole thing pops out in a few minutes.

 

Great in theory ....... sounds like it might actually work that well in practice too.

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WT & Grinna - presume you're talking a plastic thru hull fitting here?? I've got to get a plastic one out myself and this sounds like the quickest option. The nut and outside flange have both been sealed with sika bedding / adhesive compound.

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I've seen photos of the method working with a bronze thru hull fitting, but its reassuring to hear real world experience that it does work.

 

http://www.dirtysailor.com/2010/04/11/t ... t/#more-20

 

My biggest concern is that when the boat was built they installed all the thru hull fittings flush with the hull ... they're all countersunk. Unusual and hopefully not a huge problem.

 

Construction is strip plank cedar glassed inside and out, by the way.

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My hull is wooden and had and still has several countersunk skin fittings. They're lovely and flush but I've decided that the sharp edge they have is problematic as any working with age means they cut through the glass and set up hull core issues. Also, I don't like the way they diminish the hull thickness with the countersink. So I'm progressively replacing them with mushroom head types now, I think they're a better option for longevity and mechanically superior. Plastic where possible, bronze where there are backing pads( because of the body length available).

 

That cut in one method sounds good. I think I'd still prefer to deconstruct, personally.

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It's not hard at all and epoxy filler can hide lots of mistakes :wink:

When you have cut the new Hole, run some epoxy around the timber to seal it against water getting into the end grain in case it ever gets in around the through hull.

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