Removing old Thru-Hull

[ShawnL]

So, I asked in a previous thread about the need for the thru-hull for the cockpit and sink drains. I've decided to replace it and parts should be here soon. My new problem is removing the old one. I took the ball-valve and associated hoses off and put a 1' long channel locks on it and couldn't budge it. So I resorted to the largest pipe wrench I can fit into the area. And I still cant budge it. All I'm doing is chewing up the top of the bronze / brass tube and killing myself trying to pull harder (and at the right angle, which is really hard in the space) on it. I spoke to the PO's son-in-law (PO is deceased) and he thinks they worked on it at one time and epoxy-coated the tube before re-installing it.

There's a small 1/8" to 1/4" gap on the outside of the hull, between the hull and the start of the tube (which is what started this whole thing). And what looks like some raw fiberglass just aft of it that I was going to take care of when I removed it and filled the hole with thickened epoxy.

Can I fill the tube and gaps with thickened epoxy and then use fiberglass cloth over the whole thing from the outside? Would heating it with something like a blow-torch work to release it if it is epoxied in? Or. would it just cause more damage? The tube is small enough that I can't really get a saw in there to try to segment it up and get it out that way. Maybe a hacksaw blade working on my back from the bottom, but that would be a real pain in the rear and most likely not help if it's epoxied in. The more I think about it, I think glassing the whole thing over might be the best solution.

Anyone have any suggestions? Thanks in advance. The season is so short up here that I really want to get it in the water before it's over.

 

[AaronD]

I personally can't see any harm in leaving a bit of the tube in place. I can't remember - I might have done the same when I did mine (cut off with a Dremel or an angle grinder perhaps? My memory seems to have blocked that experience...)

I know I epoxied a round plug of G10 in the hole (I think it was a hole-saw core or a stack thereof from that project or others). And added a few layers of glass tape top and bottom. I suspect it's the outside layers that matter most (holding out the water pressure), but I did both. Time consuming and bit messy working in the bilge and under the boat, but not difficult.

Hope you can get her out on the water soon.

 

[BigEasy]

Grind out old thru Hull fitting from Hull surface using an angle grinder. Takes 5 minutes and no busted knuckles!

 

[ShawnL]

Got started today. I sanded the area under the boat where the thru-hull normally is. It's in a bit of a recess / channel and I had what looked like a 2" patch of chewed up fiberglass behind it. No idea how that happened. I sanded about 6" past both areas and the sides of the channel as well with 60 grit. Then cleaned with acetone and let it dry.

Came back with really thickened epoxy and filled in the bottom of the thru-hull and the area that was chewed up. Then around 8 layers of 6 ounce cloth (all I have at the moment). I started with a small strip and progressively increased the length and width. Used a trick from Boatworks Today (on Youtube) I pre-wet all of the cloth strips before putting them into place and it worked really well. Also epoxied a 3/4" chunk of plywood that I had previously coated with epoxy to the bottom of the bilge for a backing plate for the new thru-hull.

I was going to fill the old thru-hull tube with slightly thickened epoxy and glass over the top as well, but it's only in the low 60s here right now and I didn't want it to blow out the bottom or deform it. I'll probably do that tomorrow while installing the new thru-hull. I was kind of dreading this project, but it turned out to be really easy and straight forward -- aside from laying in the grass on my back under the boat and working over my head.

 

[ShawnL]

Today's progress, c-. Rain storms this morning, and I had the thru-hull disconnected. So the cockpit was full of water. Got that out with the shop vac and finished drilling the hole for the new Grayco bronze thru-hull. The directions specify a 1" hole, but I think it really should have been more like 1 1/16" or 1 1/8". I ended up having to use a rubber mallet to pound it all the way in. Sealed it with 5200 (I know, but it's a '72 and a leak will cause it to sink, so I used it). Got it all over myself and all my tools. But managed to get it in and torqued down as much as my 19 year old son could while I was laying in the wet grass holding the other end with a mill file in a pair of vice grips to keep it from moving.

Didn't want to attach the ball valve and T assembly so, the cockpit will probably be full of water again tomorrow as it's raining again. At least the location I picked for the new thru-hull doesn't seem to get any moisture from the rain near it. The hull is pretty flat there and it sheds before it gets to it.

 

[brockangelo]

You'll be happy to have the through-hull drains. That was one of the last things I did before I moved mine from storage to a slip on the water this year (about 45 minutes away). I would have never slept a wink because I had had my floor drains clog on me once and saw how the cockpit can fill up.