Agreed !
I don't remember seeing "Out of sight, out of mind" in any of the books I've read about boat maintenance.
"Who knows what evil lurks in that pile of built up epoxy under the sink ?"
Da Shadow know.
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Thru-Hull Replacement - How do I get through this mess?
- Thread starter TrapperJohn
- Start date
I don't remember seeing "Out of sight, out of mind" in any of the books I've read about boat maintenance.
"Who knows what evil lurks in that pile of built up epoxy under the sink ?"
Da Shadow know.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,988
Through-hulls are critical components on a sailboat. There is knowing or not - their condition. There is no middle ground in my world.
I had a concern regarding my through-hulls that needed resolution. I acted on the concern and was surprised by the facts.
I had a concern regarding my through-hulls that needed resolution. I acted on the concern and was surprised by the facts.
TIMING - What are you waiting for?
Timing: the ability to select the precise moment for doing something for optimum effect, On your boat, how do you judge that the timing is right? To change your thru hull. To buy new sails To change your oil To fill the fuel tank Do you count the days, weeks, months since your last change...
forums.sailboatowners.com
Well, I've finally gotten far enough to have some (but not all of the) answers.
I started with the oscillating tool with carbide bits to clear a lot of the big pile away but it was slow going. I couldn't get around the back of the valve too well because of the clearances. Then I took a 4" angle grinder with a cutting wheel to break away some larger chunks. Kept alternating between the oscillating tool and the grinder until some bronze started showing next to the valve.
This got me thinking there was more than I was expecting so I went outside and sanded away the bottom paint around this thru-hull. Lo and behold, there were three bolts and what appears to be an inset flange head. Of course, none of the bolts would budge.
After this, I went back inside and became a little more aggressive with a grinding wheel which removed most to the rest of the pile. At this point, I couldn't see any joints where the valve may have been threaded in place nor did it look like there was a nut on the thru-hill fitting either.There were no markings on the valve body that gave me a clue about the manufacturer or model. Since progress seemed so slow, I decided to cut the valve off so I could work a little easier.
From what I could see, this was a one piece thru-hull similar to the Groco models on their web site. This is the point where I realized my hull isn't as thick as I thought. My original guess was at the head discharge hull fitting which is just above the turn of the hull down to the encapsulated keel. I could feel no joint until my finger got all the way up to the ball retainer which was up much higher. I now think the laminate is about 5/8 - 3/4 inches in the area I'm working which leaves me less room for errors.
I used the grinder to work my way further down until I finally found the flange that is bolted in place. You can make out the outline in this picture.
Interestingly, there doesn't seem to be any joint where the thru-hull screws in to anything. There are no "dog ears" inside to hold or screw in the thru-hull fitting either. This is where I started to worry if this whole assembly was installed with 5200.
Looking inside the valve, I could see similar corrosion/wear to what I saw at the other valves. It's definitely pitted but there's no way to tell if the ball is actually water-tight at the seat/sealing area. (This picture isn't as clear as I thought at the time.)
The tailpiece wasn't galvanized pipe, as I originally thought, either. It's made of some type of plastic but I couldn't tell anything about it from the markings.
I still haven't gotten the thru-hull out nor anything to move. My next step is to try to cut the flange out without going too far into the laminate. Then I'll try pushing the thru-hull out.
If you got this far, thanks for reading. I wanted this to be a tutorial for anyone else that may be "blessed" with this construction technique. I'll keep you posted when this is finished.
I started with the oscillating tool with carbide bits to clear a lot of the big pile away but it was slow going. I couldn't get around the back of the valve too well because of the clearances. Then I took a 4" angle grinder with a cutting wheel to break away some larger chunks. Kept alternating between the oscillating tool and the grinder until some bronze started showing next to the valve.
This got me thinking there was more than I was expecting so I went outside and sanded away the bottom paint around this thru-hull. Lo and behold, there were three bolts and what appears to be an inset flange head. Of course, none of the bolts would budge.
After this, I went back inside and became a little more aggressive with a grinding wheel which removed most to the rest of the pile. At this point, I couldn't see any joints where the valve may have been threaded in place nor did it look like there was a nut on the thru-hill fitting either.There were no markings on the valve body that gave me a clue about the manufacturer or model. Since progress seemed so slow, I decided to cut the valve off so I could work a little easier.
From what I could see, this was a one piece thru-hull similar to the Groco models on their web site. This is the point where I realized my hull isn't as thick as I thought. My original guess was at the head discharge hull fitting which is just above the turn of the hull down to the encapsulated keel. I could feel no joint until my finger got all the way up to the ball retainer which was up much higher. I now think the laminate is about 5/8 - 3/4 inches in the area I'm working which leaves me less room for errors.
I used the grinder to work my way further down until I finally found the flange that is bolted in place. You can make out the outline in this picture.
Interestingly, there doesn't seem to be any joint where the thru-hull screws in to anything. There are no "dog ears" inside to hold or screw in the thru-hull fitting either. This is where I started to worry if this whole assembly was installed with 5200.
Looking inside the valve, I could see similar corrosion/wear to what I saw at the other valves. It's definitely pitted but there's no way to tell if the ball is actually water-tight at the seat/sealing area. (This picture isn't as clear as I thought at the time.)
The tailpiece wasn't galvanized pipe, as I originally thought, either. It's made of some type of plastic but I couldn't tell anything about it from the markings.
I still haven't gotten the thru-hull out nor anything to move. My next step is to try to cut the flange out without going too far into the laminate. Then I'll try pushing the thru-hull out.
If you got this far, thanks for reading. I wanted this to be a tutorial for anyone else that may be "blessed" with this construction technique. I'll keep you posted when this is finished.
Well, the only positive remark is that when you finish the replacement of this first valve assembly, at least you will have a complete understanding of how to attack the remaining seacocks. After viewing your dissection, you obviously had a “proper“ seacock; still a mystery of why the mound of epoxy around the valve. No doubt it’s an arduous job. obviously, the original installer had no regards for the individual who would replace them. Hang in there.
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It would be difficult for that ball to fully seal looking at its condition. It would probably weep when closed.
What a job! That's just amazing someone thought that was a good way to install those thru hulls... For sure no thought to when they would need to be changed....
dj
What a job! That's just amazing someone thought that was a good way to install those thru hulls... For sure no thought to when they would need to be changed....
dj
I wonder if a PO (we always blame the Prior Owner) tried to remove the seacock and flange at some point and damaged or cut off the nuts. When that didn't work or it became too big a job or leaked, tried to fix it with a lump of resin and glass.
From this point on as you prep the area for reglassing, a 36 or 40 grit flap disc might be less damaging than a grinding disk. The deep gouges from the grinding disk need to be eased.
@TrapperJohn - Excellent photo essay! You will be proud of your work when you are done. Please post a final picture for us to enjoy.
Thank you for taking the time to write this up and post all the great pictures. For many of these sorts of jobs, many of us don't know what sorts of things to expect until we do it ourselves for the first time. Posts like these really help the community.
I wonder if you could drill out the three bolts from the inside and get a chisel and lightly chisel around the edges of the base on the inside and maybe get it to pop off.
My 1980 boat has similar arrangement. They also used a lot of resin filler. It breaks up very easily with a sharp wood chisel. Its actually easier than grinding it sometimes. If you can pop it from the hull. A flap wheel on a grinder will take a few minutes to clean it all up.
