I just went out and purchased a Groco step-wrench. A little heat on the flange with a heat-gun softens up the bedding compound and allows you to turn the through-hull. The hard part was getting the locking nut off the through-hull on the inside. I ended-up cutting mine off as the through-hulls were definitely rose-coloured. Wood backing plates were also punky so they came off too and I made up new wood backing plates coated with epoxy (and later painted with Interlux bilgecoat). You have to shape the backing plates to the shape of the hull. I think I used 3/4-inch marine ply for mine.
All the flush-mount through-hulls I found were too small to use as replacements. So we filled the ‘cups’ with West epoxy and went with Groco mushroom surface-mount through-hulls. These had the added benefit too that they are a taper-thread so you get more than the 3 or so threads engaging with the ball valves. Another (best) option is to use flange-mount adapters on the inside but that requires either using fiberglass backing plates with studs installed or, with wood backing plates, drilling more holes through the hull for through-bolts. And those through-bolts line-up pretty closely to the edges of the filled area where the old flush-mount through-hulls were. I was concerned that the epoxy fill might not stand-up to the drilling. I might actually go back and install the flange adapters on the cockpit drains and engine intake. Quite a bit more robust solution in this area where there is a bit of potential for something heavy whacking the side of the through-hull. I recall reading of an errant spare alternator taking out a through-hull. Under the galley or head sink I can’t see much reason to use flange adapters. Peter Fell Sidney, BC Cygnet C&C 27 MkIII From: Joel Aronson via CnC-List Sent: Saturday, February 06, 2016 3:49 PM To: cnc-list@cnc-list.com Cc: Joel Aronson Subject: Re: Stus-List Replacing through hulls on a 30 MK1 It's a step wrench. Defender sells them iirc. On Saturday, February 6, 2016, Chuck S via CnC-List <cnc-list@cnc-list.com> wrote: That socket trick is slick. Plumbers use a tool for this that is fairly cheap. It is made of cast iron and has several different sized steps to fit inside the valve and capture the two tits inside. Another trick it to slide the handle of a pipe wrench or an adjustable wrench inside and hold that with another wrench. During removal, you are not turning this till the inside flange is removed, but simply backing it up. During install, you hold the outside part while tightening the inside flange. ------------------------------------------------------------------------------ From: "Antoine Rose via CnC-List" <javascript:_e(%7B%7D,'cvml','cnc-list@cnc-list.com');> To: javascript:_e(%7B%7D,'cvml','cnc-list@cnc-list.com'); Cc: "Antoine Rose" <javascript:_e(%7B%7D,'cvml','antoine.r...@videotron.ca');> Sent: Saturday, February 6, 2016 6:05:10 PM Subject: Re: Stus-List Replacing through hulls on a 30 MK1 I've done it on mine. Don't touch the flange, it's the best part. Inside the flange hole there are two notches to help you hold it while unscrewing. Buy a cheap socket (for ratchets) of the same size of the inside hole. Then grind a slot to allow the socket to slide in and lock itself on the notches. You'll need to be two for this job to unscrew the thing. It will be fairly easy once it starts moving. You'll probably be surprised at how well and healthy the hull looks underneath, this was well done. Unless the flange turned rose (meaning the zinc inside is gone), keep it and replace everything else. Antoine (C&C 30 Cousin) Le 2016-02-06 à 17:39, Joe at Zialater via CnC-List a écrit : > Howdy Listers, > > I am replacing the through hull cockpit drains on my 30 MK1. This project > started with replacing the old gate valves - and it has sort of expanded > (shall we say) from there. Mission creep! > > The flange measures 3.5 inches on the outside of the hull with a 1.25 > diameter hole. The flange is even with the hull and does not stand proud of > it. I have heard that the best plan is to grind off the flange and then > remove the through hull from the inside. > > Does anyone know brand of through hull used in 1975 and where I might find > them? I want to replace them with the same make and model if I can. > > Also any other tips and tricks would be really welcome. > > Cheers, > > Joe Boyle > Annapolis > 1975 30 MK1 "Zia" > > > > _______________________________________________ > > Email address: > javascript:_e(%7B%7D,'cvml','CnC-List@cnc-list.com'); > To change your list preferences, including unsubscribing -- go to the bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > _______________________________________________ Email address: javascript:_e(%7B%7D,'cvml','CnC-List@cnc-list.com'); To change your list preferences, including unsubscribing -- go to the bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com -- Joel 301 541 8551 -------------------------------------------------------------------------------- _______________________________________________ Email address: CnC-List@cnc-list.com To change your list preferences, including unsubscribing -- go to the bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
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