Two extra thru hulls with shut off valves

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Pack Mule

Pack Mule

TF Site Team
Joined
Jan 24, 2013
Messages
3,749
Location
USA
Vessel Name
Slo-Poke
Vessel Make
Jorgensen custom 44
We are in the middle of a bottom job and are rebedding all the thru hulls below the waterline . I have two thru hulls with shut off valves that are not being used and just have a threaded plug in the top of the valve . I can't see us ever needing these for anything .Would it be best to just remove these and rebed like we're doing the rest of them or best to just do away with and glass over the
hole ? The yard is going to have to do some glass work anyway .
 
If the yard does it properly, glassing them in is a better solution. Filled in 4 of my 5 and one transducer hole while doing my refit. Proper technique is to clean the hole. Sean did this by boring one size larger with a hole saw. Next he fiberglassed in a 1/4" thick fiberglass disc in the middle of the thickness of the hole. Then he took a 4" grinder with a course sanding disc and dished out the remaining hole on both sides. It looked like you could set a saucer in the depression. Then he fiberglassed in progressively larger circles of bi-axial cloth inside and out, to fill the depression to the level hull surface. Don't remember how many layers of cloth he used, but he would glass in 4 or 5 pieces at a time. It went much faster than I thought it would. Extremely happy with the results!

Ted
 
The next owner might love a good engine driven deck wash or fire pump.

Who knows what will be created that can use them?

I would make sure they are 100% and just leave them inplace.
 
O C Diver said:
If the yard does it properly, glassing them in is a better solution. Filled in 4 of my 5 and one transducer hole while doing my refit. Proper technique is to clean the hole. Sean did this by boring one size larger with a hole saw. Next he fiberglassed in a 1/4" thick fiberglass disc in the middle of the thickness of the hole. Then he took a 4" grinder with a course sanding disc and dished out the remaining hole on both sides. It looked like you could set a saucer in the depression. Then he fiberglassed in progressively larger circles of bi-axial cloth inside and out, to fill the depression to the level hull surface. Don't remember how many layers of cloth he used, but he would glass in 4 or 5 pieces at a time. It went much faster than I thought it would. Extremely happy with the results!

Ted
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Thanks Ted . Sounds like the right way . I sure could use your Sean about now . I feel sure the yard can handle this but I will pass on Sean's method .
 
FF said:
The next owner might love a good engine driven deck wash or fire pump.

Who knows what will be created that can use them?

I would make sure they are 100% and just leave them inplace.
Click to expand...
Thanks FF, that's a good point . I usually only think of the next owner when I'm installing something with 5200 :hide:
 
Remove them and glass the holes. No need to put a plug in, simply dish both sides and glass the hole up. Putting the disk of glass in actually results in a weaker repair than full depth glassing.
 
"Thread hijacking in progress."
My thru hulls are circa 1987 and have never been reseated. Fresh water environment. No issues to date. Is this something to add to my never-ending list?

My apologies to PM.
 
TDunn said:
Remove them and glass the holes. No need to put a plug in, simply dish both sides and glass the hole up. Putting the disk of glass in actually results in a weaker repair than full depth glassing.
Click to expand...

I believe the dishing ensures that the glassed in portion does not pop out if hit by heavy water.
Which I have seen happen. She is lieing on the bottom oh Lake Huron.
 
TDunn said:
Remove them and glass the holes. No need to put a plug in, simply dish both sides and glass the hole up. Putting the disk of glass in actually results in a weaker repair than full depth glassing.
Click to expand...

Much of the disk goes away in the dishing process. The purpose of the disc is to have a solid sufface to glass against and work out any air bubbles. If you're really worried, after glassing in the bi-axial cloth on the bottom, you can sand away the disc from the top. That's a little OCD, even for me.

Ted
 
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If you want a solid surface to glass against, start by putting a couple of layers of mat on the inside and let the resin kick. that provides a nice surface to work against for air rolling. You can remove any air from the mat by wetting it out and air rolling it on a sheet of cardboard and then laying it in place. The advantage on not glassing a disk in is that you have fabric spanning the hole for the full thickness and don't have a disk that is only held into the hole by resin. I would grind the hole inside and out to a feather edge, lat two layers of saturated mat on the inside, let it kick then lay up the outside and then the inside.
 
We would hope the yard doesn't need instructions on how to fill a hole in the hull. If it does, you need a different yard or an outside fiberglass contractor.


My boat, I would leave the thru hulls in place. I don't think it's worth the trouble and expense to remove them and properly fill the holes and repaint.
 
Are they in your way or in danger of getting broken off, if not I'd leave them as is, or remove the valve and just put a threaded cap on the thru hull pipe stub.
 
TDunn said:
If you want a solid surface to glass against, start by putting a couple of layers of mat on the inside and let the resin kick. that provides a nice surface to work against for air rolling. You can remove any air from the mat by wetting it out and air rolling it on a sheet of cardboard and then laying it in place. The advantage on not glassing a disk in is that you have fabric spanning the hole for the full thickness and don't have a disk that is only held into the hole by resin. I would grind the hole inside and out to a feather edge, lat two layers of saturated mat on the inside, let it kick then lay up the outside and then the inside.
Click to expand...

Of I see the problem. When I say a disk, I'm referring to a piece of scrap that is bi-axial cloth and fiberglass, such as a molded bench from a runabout. Simply we punch out a disk with a hole saw, The disc is secured in place with fiberglass filleting compound.

Ted
 
O C Diver said:
Much of the disc goes away in the dishing process. The purpose of the disc is to have a solid sufface to glass against and work out any air bubbles. If you're really worried, after glassing in the bi-axial cloth on the bottom, you can sand away the disc from the top. That's a little OCD, even for me.

Ted
Click to expand...

I have read of this method by several pros.

Haven't done it that way myself, but would be pretty confident in it as I do vee top and bottom......also if it was an epoxy repair and small holes in a thick hull.
 
If you decide to glass them in, I would not use a fiberglass disk in the middle.
Dish both the interior and exterior to a feather edge as others have suggested.
Next glass a few layers on both the interior and exterior at the same time. This will form a chemical bond in the open area, which is the preferred method over a mechanical bond.
 
Steve said:
Are they in your way or in danger of getting broken off, if not I'd leave them as is, or remove the valve and just put a threaded cap on the thru hull pipe stub.
Click to expand...


^^^^^^ This Marty

Rebed them and move on with life is the cheapest option unless they're in your way. You've spent enough money at the yard this year. This is a classic example of mission creep.
 
"As adhesives, epoxies bond in three ways: a) Mechanically, because the bonding surfaces are roughened; b) By proximity, because the cured resins are physically so close to the bonding surfaces that they are hard to separate; c) Ionically, because the epoxy resins form ionic bonds at an atomic level with the bonding surfaces. This last is substantially the strongest of the three. By contrast, polyester resins can only bond using the first two of these, which greatly reduces their utility as adhesives and in marine repair."

https://en.m.wikipedia.org/wiki/Epoxy

Using epoxy on smaller repairs allows greater flexibility in how they are done.
 
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If a future owner wants a through hull and seacock for a new system, it is pretty simply to install the fittings you want where they are needed. For me I would glass over the hole. as far as "dishing it out" For that type of repair a 10:1 scarf ratio is the goal. If the glass is half an inch thick you taper the laminate 5 inches out. It is best to do the repair from the outside, and much cleaner as well. grind away the glass until the periphery of the old hole is a knife edge and taper it out to 5 inches all the way around then build up with multiple layers of class. Vinyl-ester resin is a polyester with adhesion equal to epoxy and it is easier to work with. It has much better resistance to moisture than standard laminating resin. I have done it many times in my boatyard.
 
Re-bed them, don't re-bed them, just move on.

IMO, going to all the trouble to pull them out and fill the holes for no real reason is a waste of time and money. :facepalm:

Leave something for the next owner to lose sleep needlessly over for crying out loud. :D
 
Capt.Bill11 said:
Re-bed them, don't re-bed them, just move on.

IMO, going to all the trouble to pull them out and fill the holes for no real reason is a waste of time and money. :facepalm:

Leave something for the next owner to lose sleep needlessly over for crying out loud. :D
Click to expand...
Thanks , I didn't mean for this to turn into such a big deal . I'm just gonna leave them in like they are with the valves plugged .
 
Pack Mule said:
Thanks , I didn't mean for this to turn into such a big deal .
Click to expand...


This is Trawler Forum Marty, we make everything a big deal. Don't take my word for that though, right now we have a thread espousing the flipping rocket science that is Formica installation and another where grown men are arguing the difference between arcs and circles. Making a big deal about it is what we are best at.

ImageUploadedByTrawler Forum1472432041.250384.jpg
 
I'm in the "leave them in place camp" but I'd do it a little different.
First I'd make sure they were pretty short. The longer they are the more chance of them breaking off. It's a small chance but not zero.

I would then screw a bronze pipe cap on them. That should be enough, but because the pipe cap has tapered threads and the thru-hull has straight threads, I'd pack the thru-hull with epoxy putty. That way even if the cap is removed, it won't leak.

If at a later date someone needs a thru-hull, they can just replace it with a new one.
 
"We would hope the yard doesn't need instructions on how to fill a hole in the hull. If it does, you need a different yard or an outside fiberglass contractor."

I have been at "quality" yards that would plug the hole with Bondo , and then glass it over.

Yards need watching , not instruction.
 
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